This is a somewhat big job. However, if you take your time, you should be fine.
The rear axle/differential assembly could be one of three different assemblies. I attached the directions below for the 9.75" differential which is the most common.
Take a look through the directions and let me know if they help. Also, if you know that the differential is other than the one I mentioned, let me know.
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.