The Kodak holders I use have a frame that leans out to fit the film sheet under and then this pushes down to hold the film in place. You don't have to slide the sheet in
like European holders, it is a little tricky but with practice quite straight forward. I also like that the contact prints I make have a clean border, no film notch 9x12cm may seem small for contacts
but they are jewel-like in their intensity. Have fun with your camera.