Ok, if you have dissasembled the phone and assembled it back successfully, you already know the basic structure, so that's good.
The screen assembly is glued to the plastic + metal frame, and it's pretty hard to pry it apart. Make sure to use non-metallic prying tools and a heat gun (a hair drier will do fine). Using a heat gun gives you a chance to reuse the original double-sided tape, which is strong enough to keep the screen from lifting. Replacing this tape is not a good idea because aftermarket tape is not nearly as strong as the one that came with the phone (unless you manage to get 3M VHB tape).
Once you stuck the screen assembly to the frame, be extra careful when putting everything back in place. The frame has tiny clips which need to be PERFECTLY aligned, otherwise... you'll know it when you get there haha. You can leave the frame in place without the screws, it'll be easier to open it again in case something goes wrong (you wont need to open the phone from the back to access the display)
CyanogenMod-loving Xperia Mini Pro user.