Wix Membership Custom Sign Up

[dan74]

I am in the process of setting up a custom sign up form for our membership. I have been using this article:

Velo Tutorial: Creating a Custom Registration Form with Code | Help Center |...

I have a few questions:

1. How do I write to the address fields?
2. Upon success, how do I redirect to another page?
3. Upon failure, how do i message that on the UI?