I am not at all throwing cold water on you , however if you are this much of a novice, you might want to find someone to do this for you. If you do it yourself;; start by removing the bed so you can build the crossmember and mount the transfer just to the rear of the cab. Haveing done several of these as well as installing the Brown aux 3speed trans, You will have to fabricate the crossmember to handle it as well as make a shifter and linkages. This is certainly not an afternoon project nor is it something to be started in the driveway!
Foxman