How do you install the 4 in. Gray Plastic Roof Cap Vent on a tin roof?

Here is some installation guidance for the Plastic Roof Cap Vent.

The Gray Plastic Roof Cap Vent is designed to mount on a flat plywood roof and then be waterproofed with shingles. It could be used on a tin roof in the same manner, however the focus would need to be put on the sealing of the unit to the roof to prevent water leaks.