theme-app-extensions app embed

[AndyX]

When working on the theme application extension development, he encountered two problems:
1. Cannot see the extension application

https://test-chats.myshopify.com/admin/themes/current/editor?context=apps&activateAppId=8f04fd48-10a...

2. I don’t understand the relationship between the theme extension application and the APP
-Do I still need to call shopify oauth2 API on the server?

-How are Shopify’s merchants related to my own products?

My core purpose is to make an APP with such functions:

After Oauth2 authentication, call shop/get to get email, then use email to register an account for shopif merchant on my website, and then get the JS code, extend the code through the theme application, and install the merchant on the website.

[AndyX]

update.

When I am at https://partners.shopify.com/*/apps/*/extensions/theme_app_extension/*

After creating the version, you can see the extended application.

Now only the second question remains.