Hotpoint Ultra WMA76?

Washing machine:

I had to move it to tile the floor & the belt has come off, my father & I tried to put it back on & a few times we managed it but giving it a quick spin to try it out it kept comming off agian, it's not easy to get too on this model (unlike my Fathers whe he just took the back off & it was easy to put a new belt on), any suggestions?

Thanks

David