This is harder to describe then do
1) Gently shake the entire contraption. If nothing rattles around, everything is probably fine;
2) In the light, pull down and hold open one of the doors. If you peer inside, you will see the front edge of a smaller drawer, on top of a lip at the bottom of the opening. In the centre of the front of the lip of that drawer, there is a small plastic protrusion (about 1/8" x 2") which has (almost unreadable) text embossed on it - "LIFT AND PULL TO RELOAD";
3) Lift and pull the tab - the drawer will pop out about 4 inches, and in the back 4 spring loaded levers will lift up;
4) Turn all but your safelight off;
5) Load some paper into the drawer - I usually load it emulsion side down, but others might disagree;
6) Grasp the protruding drawer with one hand, and hold the entire box with the other, and push the drawer (including the paper) firmly in all the way. The front lip of the drawer should catch at the bottom, and door will close after the drawer, and the levers will push down on the top sheet of paper;
7) You may find that the levers tend to push the top sheet out as the door closes. From time to time I've damaged the first sheet when I load the safe, so I try to load it as few times as possible;
8) When you are ready to print, just open the door, and the 4 internal levers should feed the top sheet out, for you to grab;
9) Be careful to note that the door closes after you've grabbed the top sheet, and that there isn't a part of the next sheet protruding.
I'm on my second batch of these. The first lasted 20+ years. The second batch I bought used, and 1/2 of them failed soon after I got it, but the remaining half has been good for these last 2 years.