For bottom mount, after mounting bracket to post, how do you get a screw thru the inside of the mailbox bottom, bracket and spacer into post?

Thank you for your response. What I realize now is you have to drill the holes up from the bottom into the mail box and then use machine screws/nuts.

Thank you for your interest in our products Customer will need to mount the mounting plate onto the cross arm of the post first using the adapters and screw. Then they should be able to attach the mailbox for bottom mount .