Welcome to the forums.
Congrats on the MH!
The official place for the numbers, according to the WBCCI, is above and centered over the front and rear windows of your rig with the WBCCI sticker just above the numbers. However, some who prefer not to attach the sticky-backed decals to their rigs place them on a piece of plexi-glass and use suction cups to attach the whole thing to the windows for display when parked at WBCCI events. There are several threads on the subject, if you care to search for them.
Have fun and travel often!
Jeff & Cindy
'09 27FB Flying Cloud;'82 31 International
'91 350 LE MH; '21 Interstate 24GT