Form:event function and add a button

two questions: 

do you have an event function where clients can sign up for a time slot? 

if not.. 

is there a way to add a button using HTML to bring the client to a signup.com page? 

I'm not sure if I understood your question correctly. Can you please elaborate on the event action?

If you want your users to open a webpage when they submit a button, you can use the redirect to external link in your Thank you page.