How to install a screen door?
The sliding screen door is completely independent of the the sliding glass door. There is no need to remove the glass door to install a screen door. If you are not experienced at removing sliding glass doors and you try to do so, even with a helper, you risk damaging the door and personal injury.

The light sliding screen doors I am familiar with have two spring loaded rollers on the bottom (possibly on the top too). Insert the top of the door into the top slot and position the bottom as close to the bottom track as you can. Use a flat metal blade (e.g. a putty knife) to lift up one roller, push the door over the track and release the roller. Repeat on the other roller.