Use FreeForm mode if you do not need a workout program, just do whatever exercises you normally do, the watch auto tracks.
Launch FreeForm mode as follows:
The watch comes shipped with 5 exercises pre-programmed. But it is really easy to train watch to learn your exercise movement. First perform an exercise for 3+ repetitions, then follow the prompt to train:
From there on, if watch see you perform the same exercise again, it will auto log.
For exercises that do not involve wrist movement, you can manually input. You can also edit learned exercises on watch. Both accessed through the force touch menu.