Works best on seat backs with tight "full" covers (like bench seats). Pull a G/bag over the seat back, turn the cover inside-out, & starting from the top corners roll the cover on the seat back. The bag allows the cover to be moved easily against the foam instead of sticking/dragging against it. When the cover is mostly in place, reach under the cover & rip the bag out. Not necessary if you have bucket seats with a seperate hard back panel.

Again, disassembling the old seat covers is the easiest way to learn how to install the new ones (by reversing the disassembly procedure).