Activate button only

[guzmáng69297464]

Activate the next slide button not until I have two buttons on the same slide are pressed. if you not pressed for an error message

[Lilybiri]

Make the Next button invisible to start with, either in the Properties panel or (better) with the On Enter action of the slide.

For each of the two other buttons, you'll need a conditional advanced action, probably with two decisions. Can you tell what those buttons have to 'do'? When I have that info I'll write out a work flow.