Once you've got a handle on the basics, the next decision most people face is how to actually structure their week. The three most common approaches are full body, upper/lower and push pull legs, and each one suits a different lifestyle and training frequency rather than one being objectively superior.

Full body training means hitting most of the major muscle groups in every session, usually two to three times a week. It works well for people who can only get to the gym a few days a week, or who are newer to training and benefit from practicing the same key movements more frequently. Squatting or deadlifting three times a week rather than once builds skill faster, and missing a session doesn't leave a whole muscle group untouched for a week, since you'll catch it again in a day or two.

Upper/lower splits divide the week into upper body days and lower body days, typically run four times a week, two of each. This gives a bit more room to add volume to individual muscle groups compared to full body training, since you're not trying to squeeze everything into one session, while still hitting each muscle group twice a week, which research generally favours for growth compared to once weekly. It suits people with a fairly consistent four day a week schedule who want more focused sessions than full body allows.

Push pull legs, often just called PPL, breaks things down further into pushing movements like chest, shoulders and triceps, pulling movements like back and biceps, and then a dedicated leg day. Run six days a week it lets each muscle group get trained twice, similar to upper/lower, but with more exercises devoted to each pattern per session. This suits people training five to six days a week who enjoy more exercise variety and don't mind being in the gym often. Run only three days a week, it becomes closer to a once-weekly split for each muscle group, which works fine but doesn't offer much advantage over full body training at that frequency.

None of these splits is a fixed formula you have to follow exactly. Plenty of people run a hybrid, three full body days one week and an upper/lower split the next depending on their schedule. What actually matters more than the label is whether the split lets you train each muscle group with reasonable frequency, whether the volume per session is manageable, and whether it's something you'll actually show up for consistently.

If you're not sure where to start, matching the split to your realistic gym frequency is the simplest filter. Two to three days a week points toward full body. Four days points toward upper/lower. Five to six days opens up push pull legs. Pick based on the days you'll genuinely commit to, not the days you'd like to commit to in an ideal world, and you'll get more consistent long term results than chasing whatever split looks best on paper.