After removing the two screws in the back, remove the top portion of the paper tray (the part that has the photo tray). This can be done easily by simply pulling it back, away from the printer. Once you do this, look at the bottom middle of the paper tray area where you will find another screw. Remove the screw, then carefully pull out the plastic borders on the sides of the paper tray that stick out from the printer. Once you do this you can take out the remainder of the paper tray assembly without much effort.
Carefully remove the print cartridge door. This part snaps into the hinge, so be gentle.
Then you can go ahead and gently pull the top of the printer off from the back towards the front. On the front this part is held by plastic snaps. Try to wiggle a finger through the sides where the paper tray assembly used to be to massage the snaps. Gently continue to apply pressure from the back of the printer towards the front and the snaps will eventually give. There's no foolproof way to do this, just be careful and gentle.
Once you have unsnapped the top cover, DON'T just try to toss it aside. The cover is connected to the printer body by three ribbon cables. Lift the top cover a bit so that you can get a finger inside and gently disengage the cables by applying pressure from the back of the printer towards the front. After this, you can safely put the cover aside and get to work on whatever you need to do.