Beginner driving truck…..Back

Moin my name is Steve and I’m training for the BKF. I’m allowed to practice on the company property with the truck and a trailer. ( truck driver’s license I don’t have yet ) But now I have a problem driving forward and around curves works quite well. But driving backwards into the workshop I just can’t get there. Driving that until now I had to teach myself. My instructor is an ass and he doesn’t care if I can drive or not How can I drive? am I changing the way I come in backwards ?