I fly electric parkflyer, but have many glider pilots in my club. Here is the advice they give.

They always hand throw their planes before flying for the day. As you said, they take a few steps then throw it level. If it is trimmed anywhere near right, it should just float out for 50-100 feet.

Make sure you have the center of gravity where the mfg says it should be. Better to be slightly nose heavy then slightly tail heavy. Adjust the CG till it is just right and the plane glides off level and long.

After the successful hand tosses and consistant results, use the high start, but only at partal strength. And, if there are mulitple hook points on the plane, use the one most forward. This will give you the lowest, most stable launch. Make sure you hold the plane level when you release it and point it just slightly up for the first few trys. You just want a "little" more than you can do with the hand toss.

As you gain confidence, stretch the high start more each time. Then when you are really confident, move back to the center hook point, and on and on.

The key is to move up slowly, get the trim right and get the feel for the high start. Don't go full blast all at once.

ALWAYS LAUNCH INTO THE WIND. ALWAYS!!!!! EVEN AIRCRAFT CARRIERS LAUNCH JETS WITH CATAPULTS INTO THE WIND!!

But remember, you bought it to fly it. Get that bird up in the air soon. It is better to crash and fix then to hang that plane in the garage perfect and never been flown.