I am new to freediving(started 2 days ago), but I would like to increase my static apnea time and eventually work up to a 50m DNF swim(I know not to rush anything but preferably sooner than later). I have a buddy and my current static apnea time is 3:03 with my current DNF being approximately 25m. I also have access to a 25m pool. Having looked into CO2 and O2 tables, what other workouts can I do to increase these numbers? I have also heard about walking apnea, but I am unsure as to how to do this. Please help!