With a trainer the loop should be easyer than the roll. Make sure you have plenty of rubber bands holding the wing down(if thats the case on yours) climb to about 300ft. Then point the nose down about 10 degrees for the count of three ,this will build up airspeed, then just pull full back.Your loop will be a little egg shaped so after some practice let out a little elevator at the top and then reapply on the down side. good luck
later daveo