It's actually pretty easy. There's just a lot of screws and you need a T4 screwdriver. Do not try to use anything else, it has to be a perfect fit or you're going to strip the screws (that hold the LCD to the frame, not the exterior screws, which use a T6) and never be able to remove it. I believe there are 13 of them plus 8 exterior screws.
Just be careful with the flex cables, maybe take pictures after you remove something and then follow them backwards to put it back together. If you're doing the LCD (those are notorious for developing black circles on them) then you don't need any adhesive, if you're doing the digitizer/glass, make sure you order some 2mm 3M double sided adhesive and clean off all of the broken glass and old adhesive 100%. Do 2 layers of the adhesive before you place the screen on (put the adhesive on the frame) and heat it up with a hair dryer or heat gun before you put the glass back on, and keep the inside protective plastic on the screen until right before you place it on. If you don't do 2 layers then the LCD will touch the glass and it will look like there is a wet spot.