App Script help with behaviour after hitting submit

[Daniel Hodges]

I have a form as part of an app script that gathers user emails and stuff for an event. I used someone else's code which works perfectly except when the user hits "submit" at the end of the form the page stays there rather than saying "you did it" or whatever. 

I'm hoping to make that button submit the data collected and at the same time direct a person to another page.