Hi, @Dog-Tag. It sounds like you want to do some basic validation. Perhaps searching the forum for “validation” and “conditional” might turn up some results.
“Conditionals” are one of the main ways to implement logic to control the UX. They’re in a separate tab in the Properties editor.
EDIT: To expound a bit… You could, for instance, use conditionals to disable a form’s submit button until all of the fields had a value. Validation can, of course, be much more sophisticated, but getting familiar with conditionals is a good first step.
In addition to what @sudsy says (quite correctly)… Input validation is built in to Bubble in a pretty clever way. Here’s an example:
You will note that all inputs have a “this input should not be empty” field. IF you then have an action that does something with the value of that input, Bubble understands this and will handle all the (not hard to do yourself, but ya know) validation or you. Here’s one now:
So, all of the above is something that you’re supposed to notice in your first few hours of using Bubble. I guess people just don’t play around with Bubble enough because I distinctly remember seeing this and being, like, “Oh, that’s so sexy.”