https://www.julian.com/learn/muscle/intro
It's been great and I actually look forward to going now. I spend 45min to an hour there so it doesn't take up a ton of time.
I want to move on to SL5x5 after this one but go to my apartment gym which does not have a barbell. Any suggestions/comments about a smith machine (which it does have) and/or dumbbells?
Dumbbells can be used for SSLP/SL, but are not ideal:
1) They make incremental loading, which is the core of these programs, very difficult. If you're lucky, your gym will have 2.5lb increments; if not, you may have to buy a pair of 2.5 magnet weights.
2) The lower body movements in these programs are most ideally performed with barbells; there aren't really good dumbbell analogues for squats, deadlifts, and especially power cleans.
However, for strength imbalances, especially in the upper body, they can be very helpful. Many trainees end up using dumbbell bench to this end. Dumbbell OHP/military press/Arnold press is also possible and probably good for hypertrophy of the upper back.
Ultimately, though, for the best results you'll want to do the programs as intended - with a barbell.