No, you weren't doing a bad job of explaining, the explanation in the link should've worked! Just tested it & it works for me (I'm not downloading so can't preview, but it launches from within the LW library).
My computer > find your saved folder & open it. Highlight the file. Now file > open with > choose pgm > highlight the program you want to default to > tick 'always use the selected program' > ok.
I don't understand why it's not working for you