Hello
IOnlyMainRiven!
U can use the command
/iinfo what is help you a lot. Such as if there is an item in your hand just do
/iinfo and u will get the item's name and ID, like "apple 260"
If you would like to know which item's ID is 35. U just type
/iinfo 35 and you will see it is the white wool. Its work vice versa, u can add the name
/iinfo white wool and u get the answer that is 35
If you don't like commands u can check the item ID list here:
http://minecraft-ids.grahamedgecombe.com/