Undo the bolts holding the transmission pan on. Leave a few on at one end. (to let it hang down and drain some of the oil out!)
Get covered in oil while trying to drain it.
Remove old gasket from bottom of gearbox, (normally they come off with the pan.)
Gently twist/wiggle/pull the filter down until it pops out of its rubber seal.
Use a small/middle sized flat head screw driver to pry out the old seal, (maybe even a touch with a hammer if needed.)
Get a socket, or piece of round stock to fit exactly on the outer edge of the new seal, gently tap it in with a hammer, (I've found a 1/2" drive deep socket to be the best because its long enough to get to with the hammer. Can't remember the size of it.)
Lube up the tip of the new filter, put the filter on an angle with the flat bottom of the filter just about touching the valvebody inside the gearbox while trying to put in the little end into the seal. Push/wiggle/twist/encourage gently to go into its new home.
Clean up pan, remove all old metal filings, I normally take the pan out form under the car, degrease, clean, and prep for the new gasket. (Then get back under the car once its all done.)
Install pan, get all the bolts in loose before tightening any of them up with a ratchet.
I forget what torque they should be done upto, but its not overly tight, just enough to nip it up, and put some pressure on the gasket...
You can use a sealant on the gasket/mating surfaces, but I've found that you don't really need it if you do the bolts up right.
You can also use locktite on the bolts to help stop them from coming loose. But not too much otherwise it becomes a bitch when doing the service next time.
Think it should take 4.8L of Dextron VI (6)
Hope some of that helps ya mate, think I got it all