I need to open my recently acquired iMac G3 DV to adjust the focus on the screen and upgrade the HDD.

I can kinda tell that the plastics are brittle, and was wondering if there is a safe way to open it up without breaking the tabs that hold the chassis together.

I've worked with other compacts before (like the 128k and color classic), but these are completely different compared to them.

I've read the service manual for this model, and wanted to get an opinion from other users here about how to go about avoiding any breakage on it.