The launch is the first part of any flight on your discus launch glider, and being able to launch higher has many advantages: going to further thermals, allowing more mistakes, etc. Practice launching your DLG slowly and maintain proper form and rhythm without adding power. Keep practicing like that and don’t worry about height for now. After a while, the motion will become smoother and smoother, and with smoothness speed and height will come. As they say, slow = smooth = fast.