In addition to what @Tester said… do this… Jack up the rear end of your Jeep… Start the engine and see if you can put her in gear… if it grinds and sorta lets you in gear…and the rear wheels immediately start turning, your clutch is not letting go or releasing. It may be because the actual friction disc is installed backwards (it happens) or for another reason that will not allow the clutch to fully uncouple the engine and the trans.
Jacking up the rear wheels will allow you to go into gear easier esp if the clutch is not fully letting go…just be sure you are NOT in 4wd…that would be “messy”
Another “uncoupling” test you can do is to put her in gear…(with rear wheels off ground and in 2wd)…then start the engine. Push the clutch in and hit the brakes…the rear wheels should stop. If they dont or wont…it further proves the clutch cannot uncouple engine and trans…you need to investigate the why…