Building complex multi-page forms. Build from scratch? Gems?

I want to make a "new application" feature that will require several pages, form validation on each page before progressing to the next, and routing users to different pages depending on which options they choose.

What's the modern rails way of doing this, OR how would you do it? From scratch? Gems? What gems? I've read about the Wicked gem but wanted more opinions.

Edit: typo

Wicked is pretty great. It's about as simple as it gets because if you built it yourself, you'd basically be creating wicked. I don't know of many other options, but it's pretty easy to use.