To change which app opens a certain type of file, right-click on a file of the type you want to edit.
From the context menu, choose the "Open with" container, and click "Choose default program...".
Windows presents a list of installed programs that it knows can handle this type of file. You can see more options by pressing the "More options" button
Make sure that the "Use this app for all .ext files" checkbox is checked, and click on your selection. All files with this file extension will now use the app you selected.