Hi Syldania and welcome to our community
You asked:
How do I keep the project on the first slide until the user
clicks on one of the click boxes?
This would seem to imply you actually have Click Box objects
on the first slide. If so, try just double-clicking any one of
them. You should see a properties dialog. On that dialog you should
find a tab labeled "Options". Click this tab and ensure the check
box labeled "Pause project until user clicks" is checked.
If for some reason you don't actually have one or more Click
Box objects, you may insert one at any time by clicking the Insert
menu followed by Click Box.
Hopefully this was helpful... Rick