Care needs to be taken with the plastic tabs on the rear cover, especially when reassembling. They are pretty fragile and once one is broken off, the cover will not sit flush. When reassembling, start at one of the bottom corners with that side’s tabs slipped into the bottom case. When pressing down on any of the remaining tabs, one by one, use a small flat bladed screwdriver or stout plastic prise-apart tool and carefully and gently use it to push inwards directly on the tab so it has less to ‘bend’ before it snaps into place. This may be more relevant to aftermarket rear cases where you are replacing a broken case with a non-genuine replacement.
I would say jus watch out as you go from step 4 to step 5 - the white adhesive can become slightly detached from the backing as you push it onto the edge of the battery and then around to the back side. Extreme care here! Very good guide and equipment. Galaxy class!