Hi guys, could you help me with the situation below?

I have 1 screen with a Navigation Tab and 2 Tabs ("Class" and "Event"), the first tab (Class) has a form and no buttons, and the second tab ( Event ) has a continuation of the form ... when I click on the second tab ( Event ) it can only appear the content if the first form of the first is valid, otherwise I must stay in the first tab (Class) and notify the user with messages on screen about the validations ... it is a form with 2 parts.

I could use another widget to do this, but the project requires the behavior in this component... But I haven't managed to run it yet...

Thank you very much :)