If you are new to working out, the best thing to do is eat more food. Food higher in protein will help you rebuild the muscle fibers you've broken down when working out. For supplements, you can try whey protein and casein protein. "Serious Mass" is for the serious bodybuilders who are planning to pack on a lot of weight. Muscles grow due to how much food you eat. Professional bodybuilders need a few thousand calories more than the average person to maintain that mass which so that supplement is best for them.
I used to be 135-ish lbs as well and have now gotten up to 155 lbs just from working out diligently and having whey/casein to supplement my diet. You still have to be very cautious of what you eat and eat healthy because even when you're gaining, you might not gain pure muscle. For me I gain some muscle and some fat. Now I'm working to get rid of the fat and that's a pain.
Good luck with your journey!