Fitting: In my case I had to pull the turntable off its spindle.  This took a strong pull which, at first, I was unwilling to do in case it damagad something.  When I got the turntable off its spindle, I was able to position the belt round the rim of the turntable.  There was a hole in the turntable through which I was able to put my forefinger. I then put the belt over my finger and lifted the belt away from the rim. When I replaced the turntable on its spindle I was able to put the belt over the drive spindle and the job was done.  I hope your problem will be similarly solved.  Good luck!