About Ruby on Rails device User Profiles

I'm using Ruby on Rails to try to develop a web app.

We implemented the device and set up our own columns (name, age, self-introduction, etc.).

What's troubling you right now is

Create My Page to display age, name, self-introduction, etc. and
Allow users to edit their profiles themselves.

I searched various sites, but there were many articles about routing after editing the profile, so I couldn't find the article about the previous step.
While searching further, I fell in love with the device controller...

Maybe you're asking a simple question, but it's a huge challenge for me.
Please tell me who it is!

If necessary, I will prepare all the source code.