How to add cli 3 to a non-embedded React + Nextjs app?

[zxed0]

We have an existing app, a regular non embedded front end react + Nextjs app, that does a bunch of stuff, that we point our Shopify app settings to point to for installation.

In order to add app extensions, we now need to add cli 3 - we currently have no cli stuff.

there is this whole folder structure on migration guides and what not….

what’s the right way to get Shopify cli to recognize and work with this existing app - seems like we need to add the dep and toml files, but what’s Shopify actually going to do with this? We deploy our app to our hosting provider…. Is this all needed to package and deploy the ext?