First, take the cover off. Press down on the small tabs while pressing up on the big tabs. Remove the cover. Take the expansion card out, if there is one. If it is a NuBus adapter, remove the screw that holds it in place on the back and lift it out. If it is a PDS adapter, lift it out. Remove the fan by putting your fingers under it and pull up until it comes loose. Press the two tabs by the back of the power supply and lift it about 1/2". Press the silver colored tab by the floppy drive and lift the power supply the rest of the way. Disconnect the cables from the motherboard. Release the two tabs that hold the motherboard in while at the same time pushing the motherboard toward the front of the case. You can push it with the NuBus/PDS connector. Slide it until it stops. Lift the logic board out of the case. Make sure the power button clears the hole for it.
Remove the cover and disconnect the SCSI & Power cables from the motherboard. Release the two tabs that hold the hard drive in and lift it out.
CD-ROM Drive/DVD-ROM Drive
Take off the cover. Disconnect it's cable from the motherboard. Just like the hard drive, release the two tabs and lift it out.
Information provided by Doug Brown.