What OzMo and red head have already advised..............

Gliders are actually good for your situation. What is your's btw?
They can be very safely trimmed just by doing what's been suggested. Find a field with plenty of space ahead of you when you face directly into the wind. And test glide straight into the wind, power off or just enough to maintain headway. And adjust the elevator trim to get a long glide. Too short, give trim a couple clicks of up. If it stalls out of your hand, give a couple of clicks down. And if it tries to turn any time remember what the wind did just as you tossed and if the turn wasn't because of the wind, give the rudder a click to get rid of the turn.

It takes doing to get a feel for trimming their glide, but only way to learn is to do it. And you can learn to do it and do it without much drama or risk.

What was that glider?