Topcat, I haven't played this game but I found this in Chief's walkthrough.
Now the fun part: you must place the two boxes under the hatch and climb on them to go through the hatch. You will know you are in the proper position when you get the door symbol on the hatch.
To pull the box, grab it and use the directional key to move it. Jump on the boxes and go through the hatch.
If that doesn't help try this
LINK. I hope this helps.
Kay