The RG datasource can be anything you like.
I usually just use a list of numbers - then just add one number to that list (you can use text instead)
But, due to a Bubble limitation it can be difficult getting the values of the inputs out (you need some custom javascript or a plugin for that).
An alternative is to create items in the database and use autowinding - it’s a bit easier that way, and more ‘Bubble’ - but is unnecessarily costly in WU and will likely lead to a lot of orphaned data (which you can learn up using a scheduled backend WF)