You can use screws or just glue the rails under a desk or another flat surface.

Two version for these drawers:

1. Only two parts: "drawer-" and "rail drawer-".
2. Bigger version made of two parts (to fit most printers) for the drawer and additional rail. Use M2.5 screws and nuts to attach the two parts of the drawer together or again - you can just use glue.

No supports are needed for the print.