Blazer Tank Install Question

[MStokes]

I just purchased a 21 gallon Blazer tank from GMC Paul's to put in the rear of my 72 C-10. I have already cut out the small cross-member for the spare and should be ready to drill holes to mount the new tank. The main questions I have are:

The two straps that came with the kit have the ends bent different directions. How exactly is this meant to connect to the frame.

Each of the two short sides of the tank have a wedge shape that is flat on the top. Is this meant to mount flush to the bottom of the frame?

Will I have to cut the bed cross-member before I put the bed back on.

I don't have my digital camera with me or I would have posted some pics to make it easier to see what I am talking about. The kit came with absolutely no install directions.

Thanks in advance for any input.