Hey @ArkCreator! Thanks for posting on the forum, this is a great question.
To start, you could possibly have an array for holding the players’ acquired abilities, and another variable for holding the equipped ability. When you go to “equip” the ability, you set that ability from the array of acquired abilities. Another option could be to look into structs, but it definitely could depend on how you want to implement it.
Hope this can help you out a bit!
-Zen