Here is a swim workout I do usually once a week: (1 lap=25 yards)
4X25 freestyle (focusing on form)
4X25 pull buoy between legs (working arms without legs/kick)
1x25 speed (as fast as you can)
1x25 kickboard (leisurely cooldown post speed lap)
4x25 sighting (in open water you cannot see the bottom of the water so you need to “sight” where you are in the water frequently- it’s actually a lot harder than it sounds to do while maintaining form and speed).
I usually do this work at least twice but feel free to do whatever feels comfortable for you. Also its important to have a basic skill level of swimming before jumping into the pool and swimming laps. Saturday is race day!!