Push the slider forward with your finger, then lightly push the door open. It doesn't open automatically. Once it's open, the cassette holder will open automatically so you can insert a tape. Insert a tape, push the cassette holder shut, then close the door.
Thanks for the quick reply. I moved the open/eject switch forward and nudged the door "away" from the camera. Nothing - it just wont move. Is away the right direction? I dont want to force it too much.