It would be a good idea to click on the Start Here button at the top left of the page. Lots of good information on what the Gym is all about, including best practices and safety tips.
You should condition your dick before starting to use devices.
It is always recommended to start with a beginners routine and continue with it for 90 days or until you stop gaining. Start slowly and build up to the full routine over a few weeks.
Jelq with an erection level between 40 and 70%. When stretching, grab your shaft about one inch below the glans and do not pull too hard, just enough to to feel a slight stretch. Let your PIs be your guide as to how hard to peruse your routine.
Dont forget to take good starting measurements and photos so you have a solid base to compare your gains to.