Creating new customer forms

[Appsheep]

hey

how do you create a form that has “layers”, i have found an example app that can do this, but cannot understand the path to create it.

(Quotes and proposal sample app)
https://www.appsheet.com/samples/Produce-job-quotes-and-proposals-Workflows-email-quotes-and-proposa...

Are you able to show a tutorial or steps to complete this?