i just replaced one in a late model 97 ext cab. it wasnt bad at all.
if its the supercab;
fold out the bottom part of the seat, reach up underneath and you'll find 2 bolts holding it in. take the bolts out and it pops out.
there are 8 or 9 tiny nuts you have to remove, along with the seatbelts and side panels have to come out.
cut the tape **** away with a good knife while pulling the window off, dont forget to remove the 3rd brake light too.
get some good thick 2 sided tape and some glue if your picky, and install just like it came out.
i couldnt get 2 sided tape when i did mine, so i got weatherstripping glue stuff. i ran a good bead all the way around and placed the window. it had a few small leaks when i was done so i used silicone caulking to fill any leaky spots. looks great and doesnt leak now.