So I am about to run a Theros themed campaign and have been going through and adding everyone's Supernatural Gift and Devotee level Piety perks. Some are easy, like adding a spell with a certain amount of uses based on a stat. For example, I added Iroas' Devotee for one of my players, and he now has access to Compelled Duel and will get more uses if he has more CHA. But I am not sure how to add something like Keranos' Devotee where the player gets to add 1d6 lightning damage on melee attacks and is based on their INT modifier. 

To clarify, I am asking how I can add the checkbox for uses so they can just click Short/Long Rest, and it refreshes. I know I could simply add the text to their pages via Features or Notes, but I wanted to make things as simple as possible. I know how to do it when adding spells through the Feature section, but I couldn't figure out how to add things like "1d6 lightning damage" and still give it a checkbox that can be automatically modified as they level and get INT. I looked up the Nyxborn Superntrual Gift on the homebrew section, and some were able to give it the Cloak ability once per Long Rest with the checkbox, so I am curious what I am missing.   

Never mind I am big dumb. 

How did you do it?

At the bottom of actions, under save, there is another collapsed menu for limited uses fields. 

Hey, one question, you had to create a new feat for this, right?

Yep, New Feat (not choose exisiting one).

I have a Goblin Nyxborn with Piety to Nylea. 

  "At the bottom of actions, under save, there is another collapsed menu for limited uses fields. "  I

I do not see this anywhere that I can find.  I also have not been able to figure out how to add the cloak ability or the resistances.  I've been using D&D Beyond for a year now but I've done very little customizing because its so difficult to figure out.  Well it is for me anyway. I usually lack patience and get frustrated and quit before I get anywhere.  Anyone able to help me add these features let me know.  Maybe through discord someone can walk me through the process if its to complicated to explain here.

Sure I can explain it better over Discord with screen sharing. It is not too hard once you know where the poorly placed buttons are. However, I have already made a homebrew feat for the Nyxborn gift.

Resistances are easy: select Add A Modifer >  select Modifer Type: Resistance > select Modifer Subtype: Radient > Save > repeat for Necrotic. 

For the cloak of stars select Add Action > Action Type: General > Activation Type: Action >  Reset Type: Long Rest > Save > select Edit on the Cloak of Stars action (at the bottom under save there is now two new options.) > select Add Limited Uses > Type Number of Uses 1 > Save > Save.

Now Nyxborn will give you the resistances and the once a day Cloak of Stars with full functionality.

Spells are also easy. I have a player who is a champion of Nylea so I have done her's as well. When making the piety feats you will have to make each tier on its own since D&D Beyond doesn't currently have functionality for Piety scores. Anyways, to add your Hunter's Mark just select Add A Spell > Spell Hunter's Mark > Ability Score Wis > type Number Of Uses 1 > Uses By Ability Score Wis > Reset Type Long Rest > Save. And with that, you will have the limited use boxes for Hunter's Mark using this feature and it will reset all expended uses on long rest.

I have figured out a little bit on my own. I this information be good enough. I saw a video where they created an ability which I've done for lockpicking where you can adjust it as your piety score changes.  If I need Discord help I will let you know but I don't think I will.

Thanks for your help.

What about some of these:

Ephara’s Votary  

Piety 10+ Ephara trait  

You gain advantage on Charisma (Persuasion) checks while you are within a city.  In addition, when you fail an Intelligence check or Intelligence saving throw, you can reroll the die, and you must use the new roll. Once you use this reroll, you can’t do so again until you finish a long rest.

how do you add this Reroll checkbox?

Quote from LorrieX >>

What about some of these:

Ephara’s Votary  

Piety 10+ Ephara trait  

You gain advantage on Charisma (Persuasion) checks while you are within a city.  In addition, when you fail an Intelligence check or Intelligence saving throw, you can reroll the die, and you must use the new roll. Once you use this reroll, you can’t do so again until you finish a long rest.

how do you add this Reroll checkbox?

 
You can't use feats to do re-rolls so that's just descriptive text.

You can use "Limited Uses", as detailed above, to make a checkbox you can manually check once you have used it.

For more details about those little checkboxes, see the Subclasses & Races FAQ #4: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq).

thank you!

Happy to help.