i find the packaged stuff hard to work with..i have no idea why..i just do.
i cut my strips around 2 to 2.5 inches..width of fabric. i like to use what is left over from the project at hand..just me.
you sew on the binding on the front, then some hand sew to the back.
some find it relaxing..i have hand issues, so i don't do it that way..i machine sew them on, or barter the job with my friend, 'she hates cutting! works for me!
there are so many videos out there, tutorials, it is easy to watch and then do.