How many times a week should you train?
The simple answer to this is; realistically, how often can you do it?
If you can only get two thirty-minute workouts per week, then programming four-hour-long workouts will only increase your stress levels, increase the likelihood of you feeling like you have failed and definitely increase the chances of you giving up and not trying again.
In an ideal world, we would hit each body part twice per week, so that we can add a stimulus to the chest, back, shoulders etc regularly.
So with this information, you can start to plan out your workouts. If you can train twice per week, then aim for two full-body workouts.
If you can train three times per week, aim for a push day, a pull day and a full body day - or an upper day, a lower day and a full body day.
If it's four days a week, then you can do push, pull, push, pull workouts.
I hope from this, you get that there is no magic way of doing it. You need to find some workouts that you enjoy, that you can see yourself doing for a decent amount of time, get your head down and do the work.