Ensure the glass lines up with the edge of the iMac
After replacing the adhesive strips with new ones and the screen connectors have been reconnected, place the lower edge of the screen on the bottom shelf” to take the weight, but don’t press it back in the shelf too much.
At this point if you’re careful you still have the ability to ensure the edges of the glass line up with the aluminium edges. As soon as the adhesive strips make contact with the glass you will quickly lose the ability to adjust this to line up.
When re-attaching the speaker connector, also pay special attention to pushing down firmly on this to ensure a connection is made. Again, not too hard, but it is easy to push down enough to think it is connected but it can easily not be.
Very straightforward replacement.
Take special care when removing the microphone and speaker connectors from their respective sockets. Just be gentle and methodical.
Ensure you press down firmly, but not hard, after microphone replacement when reconnecting the battery connector to the motherboard.