Personally I have two days per week dedicated to upper body exercises. Day 1 is mostly chest/tri, day 2 is mostly back/bi. Day 3 is mostly legs. If I get a 4th day in, it's usually supplemental work with DB's or
other exercises I want to hit within a week. Not delimited to this, but that is my
general structure.
Haven't always done it this way. When I was younger and recoup time was a lot shorter, I was on a fullbody workout plan where I'd hit everything each day I was in the gym, utilizing different exercises per day, focusing mostly on the exercises that would benefit swimming.
What are your goals?