No place for my grass bag catcher to sit on

[Newby Lawner]

I recently bought a used troy bilt tb160 and it didn’t come with a grass bag catcher. So I ordered and recently received he frame and bag for the mower. 21”. As I open the rear door of the lawn mower where the bag usually sits/mounts onto, I notice there isn’t any where for me to mount the bag onto. So now I’m lost. Not sure if I’m missing a bracket or part. Any help will be great. Thanks.

 

[Rivets]

Maybe this manual will help. http://manuals.mtdproducts.com/manuals/769-17232.pdf