My camper is older, but the concept should be the same...
The "button" tops should pop off using a screwdriver, or something similar. Sometimes just your fingers will do.
That will expose the screw head that is holding the curved board on.
After removing that board, you'll have to get creative as to what to do next...
"rolls down one hill, can 'ardly make it up the next..."
1999 21' Wildwood WDF21RK
2006 Dodge Ram 2500, 4x4, Quad cab, 5.9L Cummins, 3.73 gears.