Kyocera FS-C1020MFP - Manual (Page 128)

When loading custom size paper, position the paper guide slightly wider than the actual paper size.
Pinch the front end paper guide and slide it inward to match the standard size.
When loading custom size paper, position the paper guide slightly wider than the actual paper size.
Load the new paper stack print side up.
Make sure paper is not stacked higher than the upper limit (upper line) marked inside the tray.
Slide the guides inward, until they are flush against the paper's sides.
Make sure the paper is not stacked higher than the projection on the side paper guides.