John Deere D170 54" Bagger

I recently purchased a John Deere bagger for my D170 tractor. I started the assembly but was interrupted and didn't get back to it for several days. Of course, now I can't locate the instructions and can't find them online. John
Deere told me I would have to get them from the dealer. I asked that they be emailed, as I live over an hour away. That was a couple of days ago and I still haven't received them.

So, I tried the assembly through intuition and now I have the unit working. Only problem: I couldn't get the belt loose enough to get the blower on without use of brute strength. From what I see on this forum, the unit should go on and off easily. What did I do incorrectly?

Thank you in advance!

MJP