I replaced the clutch on my '85 4x4 Ranger myself. Only hard part was getting to the top bolts, ...and bleeding the hydr sys. I tried to save a few dollars and went with AutoZone parts and it lasted 29 days then the pressure plate came unglued. I went back with Ford parts the 2ed time
Basically the clutch is between the crankshaft and transmission, the transmission is stuck inside the crankshaft. To remove the clutch the transmission has to come out of the crankshaft. There is a special procedure tighten the pressure plate to keep things align along with special tool and special jack. You don’t want to get one single greasy finger print on anything, but you do want to grease certain parts without using too much or too less of grease. Not installed and adjusted correctly the clutch won’t pull your car out of the driveway and it will be rendered useless, shot, money down the drain.
I agree with rcm600, it’s more to it than changing a spark plug.