When you right click on a file and click on "Open with", you could select a listed program to open the file with that program for just that one time. This is what this tutorial is for to add programs to this list.
If you used the "Choose default program" option in the "Open with" context menu, then you have a choice to make it the default program or for just that one time. If you don't want the program to become the default program, then you would uncheck the Always use the selected program to open this kind of file
If you like, you could use the tutorial below to have the Always use the selected program to open this kind of file
box unchecked by default instead of checked to help. "Always use selected program" - Always Checked or Unchecked
Hope this helps,