With the Paterson spirals (with balls in the lead-in) there's no bother, the balls grip the edges of the film, it loads exactly like 35mm film.

The trailing end of the film is loose. In the changing bag, start unwrapping the backing paper, when you can feel the film come loose load it into the spiral, then back-and-forth until the stuck end of the film is reached. Tear the tape from the backing paper (the tape stays stuck to the film, this doesn't matter), advance the film wholly into the spiral, assemble the tank with the spiral inside, remove loaded tank, scrap backing paper and spool from changing bag.

Don't forget that more liquid is needed for a 120 film!