Open Gym is your time to train on your own program. Daniel is usually around for the Monday morning block from 5:30 to 8am, and there is trainer support available across the week if you want a pointer.
Treat it like your own personal gym. Do your own strength program, hit the boxing bag, jump on a spin bike or a rower, use the sauna, whatever you are feeling on that day.
Members also get an After Hours pincode for access, so you can get a session in outside the staffed times, whenever it fits your schedule.