You've figured out the exercises you should be doing, but what about the number of sets and repetitions? Your decision should be based on your goals. The American College of Sports Medicine recommends 8-12 reps for muscular strength and 10-15 reps for muscular endurance. They also recommend at least 1 set of each exercise to fatigue although you'll find that most people perform about 2-3 sets of each exercise. In general:
HMB supplementation is claimed to build muscle size and strength and promote fat loss in conjunction with a strength program. Studies of HMB have shown some benefit to strength athletes in building muscle bulk but the benefits are relatively small and the cost of HMB is high. The effective dose seems to be 3 grams/day divided into 1 gram three times a day. Probably not worth taking. Beta-alanine is the new guy on the block and has not been evaluated sufficiently in my view. It may provide some advantage in high-intensity sports like weight training but it’s much too early to know that it does. Some early studies are flawed. Save your money or try creatine instead.
If you’re a beginner, you should train with three full-body workouts per week. In each one, do a compound pushing movement (like a bench press), a compound pulling movement (like a chinup), and a compound lower-body exercise (squat, trap-bar deadlift, for example). If you want to add in 1–2 other exercises like loaded carries or kettlebell swings as a finisher, that’s fine, but three exercises is enough to work the whole body.
Beta-alanine is a naturally occurring non-essential amino acid that comes into the body through foods that are rich in protein. The performance-enhancing aspect of beta-alanine (BA) is due to its ability to increase intra-muscular levels of carnosine. Increasing beta-alanine through supplementation may raise carnosine levels by over 60 percent in as quickly as four weeks.[6]
Synthesis primarily takes place in the kidney and liver, with creatine then being transported to the muscles via the blood. The majority of the human body's total creatine and phosphocreatine stores is located in skeletal muscle, while the remainder is distributed in the blood, brain, and other tissues.[17][18][20] Typically, creatine is produced endogenously at an estimated rate of about 8.3 mmol or 1 gram per day in young adults.[16][17] Creatine is also obtained through the diet at a rate of about 1 gram per day from an omnivorous diet.[17][18] Some small studies suggest that total muscle creatine is significantly lower in vegetarians than non-vegetarians, as expected since foods of animal origin are the primary source of creatine. However, subjects happened to show the same levels after using supplements.[21]