Rtv is easy, just put a decent sized line around the cover and bolt holes. Then let it dry for 10 minutes to sorta cure it outside. Then put the cover on and bolt it in a star like pattern.. When you take the bolts off to the cover it wont just pop off either, you need a rubber mallet to gently bang the cover with and itll eventually pop off or get a screw driver and hammer and gently whack the edges and eventually itll break loose. Brake cleaner on the differential gears will help also to clean it up
Make sure you remove the cover and differential of the old gasket material. Use a razor blade or something, and dont scratch it
Oh and fair warning, use cloths that are ripped and stuff that you dont care about. The differential oil STINKS bad and you will never ever get the smell out of clothing.
2013 6.2 V8 Camaro SS 9k miles
1998 5.9 V8 ZJ 180k miles
1998 4.0 I6 Laredo ZJ 227k miles