The cover appears to be well made.  However, there is absolutely no practical way to install it without ripping or tearing it on the corners of the cupola or main roof.
It would require 4 people on tall ladders, one at each corner of the gazebo, and an absolutely windless day.
First, however, you would need to completely unfold it on a large flat area in order to determine where the doors and windows are located.
Then your 4 people on ladders would need to pull the heavy cover up over the roof, without making contact with any of the corners or sharp edges...which is essentially impossible.