I've been a heavy equipment mechanic for 20 years so a manual transmission is simple to me. Depending on a lot of things, it may be easy for you too, or maybe not.
There is no black magic in a manual gear box, but there are a suprising number of small pieces. The best advise I can give you is to get a good (I perfer factory) service manual and read through rebuilding your transmission. You will know what tools you will need and you will get a feel for your ability to tackle the job.
If you don't already have a GOOD service manual (not the generic auto parts store type), you should get one anyway. They are a life saver sometimes. I got a factory Toyota manual for my 1980 on E-Bay for $7.50 including shipping. I got a factory Toyota manual for my boy's Tacoma for $20 on E-Bay. I know the factory manuals are a hundred dollars or better in most cases, but I would pay the full price if I had to. I really think they are worth it.
Where are you located?