Turn the chair upside down so you can work easily.
Lay the chair leg plate in the corner, where the leg will be. Line the plate up with the edges of the chair and so the screw holes rest on the wood frame of the chair.
Outline the plate using a pencil and mark the holes for the screws. This will allow you to put the plate back in its correct spot when you are ready to attach it to the chair.
Remove the plate from the chair, then use a hammer and a nail to make indentations in the wood frame where the marks for the screw holes are. This will give you starter holes for your screws.
Return the medal plate to the chair frame, lining it up with the marks on the frame that you previously made. Then insert one of the screws into one of the starter holes you made and screw it into the wood using a screwdriver. Screw in all four screws to complete the project.