Redzone Guide Question

I'm a little mixed up on the fullhouse plays.

For the FB Slam, it says:

1. Slide protect up
2. *Motion the HB on the right (of screen) to the left
3. Snap once he passes the center


I'm assuming (perhaps incorrectly) that all the backs are referred to as HB. Isn't the HB on the right the one doing the slam?

It also says:
*If we flip the play, Motion the HB on the left (of screen) to the right


I'm asking because this motion is key to a lot of the plays working off of each other.


Thanks!