Mark has them both right.
Test fit those short pieces & they should wrap perfectly on the front of seat cross member, just between the raised areas on the side, then mark & mask the floor so you can spray that surface neatly without too much overspray clean-up afterwards (assuming you're using one of the 2 surface spray adhesives like 3M 77, 90, etc.).
Do the same test fit, mark & mask for the rest too, but only spray a couple of small or 1 large piece at a time (spraying both floor area & leather backside) to give you enough out-time/dry time to get it positioned & on comfortably. Use a couple-a-3-4 long wooden dowels from Home Despot/Lowes to lay under the leatherette to prevent contact with the sprayed floor surface while you position & smooth-out & roll it on, moving them out of the way while working from one end to the other.
If you've ever done Formica/etc. with 2-surfact application contact cement - it's a similar process. A small rubber roller helps with the final step of pushing the vinyl into the floor/cement, but a sturdy new/unused small paint roller can work, but requires more going back-n-forth since you can't push it as hard into the vinyl/floor.
Good Luck!
Tom
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