How does one associate a file type (extension) with a specific application in Linux Mint?
It’s actually very simple. Run the file manager (Caja), right-click on the file, select Properties and the Open With tab. Now, click on one of the radio buttons for the listed applications. As the message at the top of the window states, this will “…open <the selected file> and other files of type <selected file type>…” using the selected application.