80 cj7 tub swap (first one)

Picked up a 1980 cj7 with the 4cyc in it. Frame is in amazing shape and was fully re done by a local shop. How ever my buddy ran out of cash n brought it home with out doing the tube so now I bought it off him for what he owed the shop for redoing the entire frame. Well I wanna know how hard its gonna be for me to swap the tube for a tub I got off craigslist that's rust free. Iv never done a tub swap n this is my first jeep. I can weld and I got plenty of tools. So how hard will it be and how long will. It take and what all will I need?

Thanks jesse