How to associate a file extension with an app? I have a number of files with some extension and I have an app that can open the files - it is not the default format of this app, but it can import and display it.

At the moment when I attach USB stick with these files File Manager display error message "This file cannot be opened".

I need to open the app, choose "File -> Import" navigate through fairly complex directory structure and only than I can see the content.

How to create file association so I can immediately open the file from File Manager?
After trying various options I finally found the app that works for me. Total Commander has a number of associations and also allows you to associate a file with any app. Therefore I simply always use tc for browsing files and voila, it works.