Ability to install apps not in the app store

I’ve seen this asked before, but no one answered the post. How do we install apps that are not in the app store? Thanks

Do you have an example of an app you’d like to install? If you want to create your own app store you can do so, and add your own dockerised apps.

However, may I suggest that if you want to add your own dockerised apps, that you consider submitting them to the Umbrel store too?