Tray carrying advice?

Hi everyone! I just got my first hospitality job as a server in a cinema. We practiced carrying trays with drinks today and I found it so difficult!

My main issue is how heavy it was- thee full drinks on a tray. I'm a small person and not very strong, also very prone to injuries and only doing it once I found it very heavy and ended up hurting my wrist and arm in the process.

Is there anything I can do to prevent this in the future? I'm worried about starting the job and being in pain or worse dropping the tray because of it. Please help!