Definitely go rogue route and pump in dex so you have a high ac as a class feature for character because there small they get +1 to ac then go assassin route by level 7 if your duel wielding daggers you can do a maximum of 120 attack damage. That’s not even adding poison if you get it. Also because of the low con your gonna want to pump in there to after dex so you get hp fast make it your second highest stat. Try to use pact tactics as much as possible for advantage on attacks along with cunning action to hide and take another sneak attack next turn. 
this is for if you want to make a kobold character 

My kobold, level 10 valor bard, level 7 beastmaster ranger, panther mount or a pteranodon to fly, sharpshooter, I can use my bonus action to command my mount to dash (7th level beastmaster ability), plus buff it with longstrider and haste and if I had arrows of slaying unlimited(200 would be more than enough) I could even solo tiamat outside her lair with massive open area (few miles), if I use my A and BA to command my mount to dash, I get 360ft speed (panther) or 420ft (Pteranodon) with 600ft bow range, do that here, there and the round before haste needs to be recast, tiamat could dash every round and never catch me,that's right, A level 17 soloing a CR 30 under the right conditions... R.I.P Spurt, you were the inspiration behind this character, Spurt was a kobold inventor. He was played by Chris Perkins

Quote from Darastrix_the_kobold >>

My favorite character I made is a kobold 

 agreed

Yay! now I know what a kolbolds hp and ac is!!!!!

Bout to pair one of these scaley bois with a couple of raptors

Once my party pretended to be a kobold fire gods at lvl 1. It worked and we to what we were looking for and left well they groveled before us. It was super fun.

Quote from Samso1 >>

Once my party pretended to be a kobold fire gods at lvl 1. It worked and we to what we were looking for and left well they groveled before us. It was super fun.

 That's awesome.

Are they resistant to fire damage? Do they all have reddish scales, or does it vary? If so, does the color have an effect, and what is it?

Quote from Wolffish_Grin >>

Definitely go rogue route and pump in dex so you have a high ac as a class feature

 What class feature provides you high ac exactly?

Quote from Wolffish_Grin >>

because there small they get +1 to ac

 Not in the 5e, they don't. It was true in f.e. 3.5e.

Quote from Wolffish_Grin >>

go assassin route by level 7 if your duel wielding daggers you can do a maximum of 120 attack damage

1. dual wield shortswords if you want damage

2. you probably count sneak attack on both hands which is wrong because you can apply sneak attack damage only once per your round.

Also "Though fight comma every now and then does make life more interesting post more comprehensible, don't you think?"

Quote from Helmut_McQuack >>

Are they resistant to fire damage? Do they all have reddish scales, or does it vary? If so, does the color have an effect, and what is it?

 That’s a great question.

Most Kobolds have absolutely no magic or elemental affinity whatsoever, whatever Draconic connection they may (or may not) have is simply not strong enough.

However, there are exceptions who do have resistance to a damage type, and in extreme cases innate magic.  These wind up as “priests” leaders, and tribal champions later in life (the Dragonshield is a more mature form of this).

I can see

Quote from Dr_Frederick >>

Quote from Helmut_McQuack >>

Are they resistant to fire damage? Do they all have reddish scales, or does it vary? If so, does the color have an effect, and what is it?

 That’s a great question.

Most Kobolds have absolutely no magic or elemental affinity whatsoever, whatever Draconic connection they may (or may not) have is simply not strong enough.

However, there are exceptions who do have resistance to a damage type, and in extreme cases innate magic.  These wind up as “priests” leaders, and tribal champions later in life (the Dragonshield is a more mature form of this).

 Where'd you get that they don't have magic affinity? From earlier versions to even now the books have made a point they heavily use magic.

Quoting Guide to monsters here, "Unlike some other humanoids, kobolds don’t fear or shun arcane magic. They see magic as part of their connection to dragons, and are proud to be blessed with the ability to wield such power."

3.5 to 4 feet tall

I just realized i actually asked that. That mustve been before i really got into dnd i didnt even spell kobold correctly thanks also it normally says 2-3 feet tall goblins supposedly can get 4 foot tall but ive always seen them normally 3 foot

How do you get get this for the character builder?

You need volo’s guide to monsters.

If you roll their hit points as listed (2d6 - 2), 1 out of every 36 kobolds begins combat unconscious (at 0 hit point).

It would make sense for them to be similar to dragonborns

Man, these guys are so versatile. I really enjoy my DM playing them as tricky little guys that know how to run! It keeps some early game playtime interesting and engaging. Highly suggest using them 10/10.

how much do they weigh?