I googled and found a picture of the back. Looks like a standard "move the slide, open back" type setup but it's hard to say as I've never dealt with these things before. Generally the rule with working with antiques (and most any other camera) is don't force it. If it isn't going to move with gentle movement, it shouldn't be moving usually.
There will be a spool inside usually, you should take it out and put it where the winding knob side is inside and make sure the winding knob connects into the spool. Then you can put your new roll of film in the (usually left hand)side you just took the old spool out of. put the pointy bit of the backing paper into the other spool, turn it a little ot make sure it's on the takeup spool then close the back. Generally these things have a little window in the back so you can slowly keep turning the knob until you see the number 1 appear.