frontside and blindside are done very differently.
on a frontside, pop onto the box or rail normally, but keep your shoulders facing towards the end of the jib, so you never turn sideways. angle your leading ski up a bit so it is on the inside heel edge. use this to grip the box and pull with your heel. popping a tiny bit will give you the spin you need to change sides, once youve popped it around keep your shoulders turning back up towards the top of the box so you come out switch.
for a blind, i set it as i pop onto the rail. turn your shoulders to your natural side as you pop on so that they want to face back up towards the top of the box, and keep your head turning so that its looking at the end of the box again. the first couple times, you should keep your feet down and let yourself spin on the box. after your comfortable with that, do the same shoulder turn when you pop on, but as yhou start to spin around just hop a little bit. the most important thing to remember on a BS sw up is to turn your head so that you are looking back down at the end of the box, not your feet and not the beginning.