Starting at 1st level, thus, the Monk does a single attack when he takes the Attack action. Using Martial Arts, assuming he's unarmed or is using a monk weapon, he can use a bonus action to take a second attack (more or less like dual-wielding).
At 2nd level, after the monk takes the Attack action, he can opt to spend a Ki point to do two attacks as a bonus action (for a total of 3). Note that this is also a bonus action and doesn't stack with standard Martial Arts.
At 5th level, the monk's Attack action allows him to make two attacks. This doesn't conflict with either Martial Arts or Flurry of Blows. At this level, the monk has the option to do 2 attacks (Attack action only), 3 attacks (Attack action and Martial Arts-granted bonus action), or 4 attacks (Attack action and spending a Ki point for Flurry of Blows).
What Onyx said is correct, but to clarify your question: you could use your bonus action to make a second attack using dual wielding, but you wouldn't gain anything versus using your bonus action for flurry of blows
Martial Arts needs unarmed strikes or monk weapons (shortswords and any simple melee weapons that don’t have the two-handed or heavy property). Flurry of Blows can only be done with unarmed strikes exclusively (although your Attack action for it can be with whatever you want).
Two-weapon fighting need the light weapon property (that Unarmed Strikes lack). Unless you have the Dual Wielder feat, but even then you need one-handed melee weapons (which your fists aren't).
You can use two-weapon fighting with two monk weapons, if you want to, but unless you have something like the Fighting Style that is also called "two weapon fighting", such as available by the fighter, the bonus attack's damage doesn't benefit from your ability modifier, so you're worse off than simply using Martial Arts.
I guess my thing is, under Martial Arts, monks can make an "unarmed" bonus action attack anytime they use the attack action that uses a monk weapon or unarmed strike. it's essentially like 2 weapon fighting in monk style. Why is this even an issue?
It seems that your monk wants to be able to take an additional Bonus Action, but you are only allowed 1 Bonus Action per turn. Making a second attack while two-weapon fighting is your Bonus Action. Making a second unarmed attack as a monk is your Bonus Action. You can't do both.
Martial Arts needs unarmed strikes or monk weapons (shortswords and any simple melee weapons that don’t have the two-handed or heavy property). Flurry of Blows can only be done with unarmed strikes exclusively (although your Attack action for it can be with whatever you want).
Just to clarify: the Martial Arts feature is triggered by using the attack action with either an unarmed strike or a monk weapon (shortswords and any simple melee weapons that don’t have the two-handed or heavy property). However, the resulting attack may only be an unarmed strike. But this does not count as an unarmed strike (edit: off-hand attack) so your full Str/Dex modifier (whichever you choose) is applied. Sometimes the monk weapons can be altered (for instance, with the Kensai subclass) but the Martial Arts feature rarely is.
It seems that your monk wants to be able to take an additional Bonus Action, but you are only allowed 1 Bonus Action per turn. Making a second attack while two-weapon fighting is your Bonus Action. Making a second unarmed attack as a monk is your Bonus Action. You can't do both.
That is correct, Onyx's first post sums the Monk's options up nicely
But this does not count as an unarmed strike so your full Str/Dex modifier (whichever you choose) is applied.
Did you mean to say "this does not count as two-weapon fighting"?
Actually I meant "it does not count as an off-hand weapon", so basically we're talking about the same thing :P (typing faster than my brain... durrr...)
my monk wants to know if he hits 2 times normally, can he use a bonus action to do another attack like with dual wielding weapons?
I'm not certain about the context of your question, so I'll try to tackle the general usage.
The monk has three relevant abilities for attack numbers: Martial Arts (at 1st level), Flurry of Blows (at 2nd level), and Extra Attack (at 5th level).
Starting at 1st level, thus, the Monk does a single attack when he takes the Attack action. Using Martial Arts, assuming he's unarmed or is using a monk weapon, he can use a bonus action to take a second attack (more or less like dual-wielding).
At 2nd level, after the monk takes the Attack action, he can opt to spend a Ki point to do two attacks as a bonus action (for a total of 3). Note that this is also a bonus action and doesn't stack with standard Martial Arts.
At 5th level, the monk's Attack action allows him to make two attacks. This doesn't conflict with either Martial Arts or Flurry of Blows. At this level, the monk has the option to do 2 attacks (Attack action only), 3 attacks (Attack action and Martial Arts-granted bonus action), or 4 attacks (Attack action and spending a Ki point for Flurry of Blows).
I hope that makes sense.
What Onyx said is correct, but to clarify your question: you could use your bonus action to make a second attack using dual wielding, but you wouldn't gain anything versus using your bonus action for flurry of blows
The two-weapon fighting rules require light melee weapons. Unarmed strikes aren't weapons, and they don't have the light property.
The Forum Infestation (TM)
Following up on what InquisitiveCoder said, also under Martial arts and Flurry of Blows the bonus action attacks MUST be unarmed strikes.
As per the above comments, for completion's sake:
Martial Arts needs unarmed strikes or monk weapons (shortswords and any simple melee weapons that don’t have the two-handed or heavy property). Flurry of Blows can only be done with unarmed strikes exclusively (although your Attack action for it can be with whatever you want).
Two-weapon fighting need the light weapon property (that Unarmed Strikes lack). Unless you have the Dual Wielder feat, but even then you need one-handed melee weapons (which your fists aren't).
You can use two-weapon fighting with two monk weapons, if you want to, but unless you have something like the Fighting Style that is also called "two weapon fighting", such as available by the fighter, the bonus attack's damage doesn't benefit from your ability modifier, so you're worse off than simply using Martial Arts.
I guess my thing is, under Martial Arts, monks can make an "unarmed" bonus action attack anytime they use the attack action that uses a monk weapon or unarmed strike. it's essentially like 2 weapon fighting in monk style. Why is this even an issue?
It seems that your monk wants to be able to take an additional Bonus Action, but you are only allowed 1 Bonus Action per turn. Making a second attack while two-weapon fighting is your Bonus Action. Making a second unarmed attack as a monk is your Bonus Action. You can't do both.
unarmed strike(edit: off-hand attack) so your full Str/Dex modifier (whichever you choose) is applied. Sometimes the monk weapons can be altered (for instance, with the Kensai subclass) but the Martial Arts feature rarely is.Subclass: Dwarven Defender - Dragonborn Paragon
Feats: Artificer Apprentice
Monsters: Sheep - Spellbreaker Warforged Titan
Magic Items: Whipier - Ring of Secret Storage - Collar of the Guardian
Monster template: Skeletal Creature
Did you mean to say "this does not count as two-weapon fighting"?
The Forum Infestation (TM)
Subclass: Dwarven Defender - Dragonborn Paragon
Feats: Artificer Apprentice
Monsters: Sheep - Spellbreaker Warforged Titan
Magic Items: Whipier - Ring of Secret Storage - Collar of the Guardian
Monster template: Skeletal Creature