Glad to see you got it running!
I couldn't really tell from the video if the belt was on the right way of not. It does look loose enough though. Here is a video with the belt on the right way.
I ran my first one with the belt on the wrong way for a couple weeks. I always wondered why the garage smelled like burnt rubber. Then I realized you could put the belt on the other way and it didn't rub against itself. No more smell!
The shipping bracket is in this video. I also didn't know it needed to be removed after placing the boiler. The motor/fan bracket sits on an adjustable rubber foot on the floor. The foot has an adjustment to set the fan spacing.
-Don