If getting big is your goal, then you are referring to hypertrophy. That is packing on lots of muscle. This can be done with the proper frequency and intensity.
Frequency
If your goal is to get big, I suggest lifting 2-3 times a week to start. We want the minimum effective dose to elicit the most amount of change. Anything beyond that is excessive and leads to junk volume for no additional benefit. I am a fan of this approach because, for a natural lifter, our way to get growth is by sending a muscle building signal to each muscle. When we lift appropriately, that signal elevates for 24-48 hours. After that, it comes back down to baseline. Knowing this, to optimize our growth, we’d want to send that signal again once it comes back down. This is why I prefer a push/pull or full body approach versus a body part split. It will keep spiking that signal once it comes back down.
I recommend incorporating higher frequency programming of 5-6 days a week as you advance through your lifting career, when find you are no longer making gains from the first approach. This may look like a plateau in your lifts, and feeling like you aren’t seeing any progress after each mesocycle. Keep in mind this involves adding more volume, as that can help elicit the change mentioned earlier.
Volume and Intensity
When starting out, aim for 10 weekly sets per muscle. So, for a 3-day split, that would be 3-4 sets per muscle per workout. You will be getting the most growth from this. As you become more advanced, that number may increase to 12-15, and then 15-20. Again, be careful adding too much volume too soon. More isn’t always better. Instead focus more on the quality of those sets. How many QUALITY sets do you need to see change? Do not exceed more than 8-10 sets per muscle in a given workout. Any more than that will not elicit more gains. In fact, you’d be better off splitting that up over those 3-6 workouts in smaller volume doses. That will allow you to hit those sets fresher, which allows you to use more weight and thus stimulate better growth.
Progress
As mentioned before, try to add 1 more rep or 5 more pounds than the week before. This will ensure you are utilizing the proper intensity within your workouts and not lifting too light or too hard. Choose a weight that allows you to stay 1-2 reps shy of failure.
Recovery
As you increase reps or weight week to week, you will notice that the progress eventually comes to a halt. It would be amazing if we could forever add an extra rep or 5 pounds but that isn’t the case. If you do see your stall for more than 1 week, take a deload. This gives your body a chance to recover, and take all the volume you accumulated and catch up. Muscle also strengthens quicker than the joints and connective tissue. We want to give our joints and tendons a chance to catch up to that muscle growth, so we don’t risk injury by moving the weight our body ready for.