Auto Responder Message

Hello

I have created a webinar page on my website, on this page, I added multiple webinars, and each Webinar has individual buttons, if anyone clicks on the buttons, the contact form pop-up appears, we want 1 single contact form when someone clicks any button and fills the form they get different auto responders messages over the email. can you please help me out with this issue?

Reference Website: https://www.veneratech.com/webinars/