Lots and lots of pictures. If nothing else, take a look at Step 6 (the SIM slot), and Step 12 (the L-shaped battery).

From the conclusions:

• Critical display and battery repairs remain a priority in the iPhone’s design.
• A broken display can be replaced without removing the biometric Face ID hardware.
• Liberal use of screws is preferable to glue—but you’ll have to bring your Apple-specific drivers (Pentalobe and tri-point) in addition to a standard Phillips.
• Waterproofing measures complicate some repairs, but make difficult water damage repairs less likely.
• Glass on front and back doubles the likelihood of drop damage—and if the back glass breaks, you’ll be removing every component and replacing the entire chassis.

That last bit is an issue. Here’s a post from 9to5Mac that shows off a variety of drop tests. Check out that image at the top, which shows shattered back glass.