I moved over the rocks by the water hose and made a concrete wall that will both hold the bricks in, and the rocks on the other side.
I had to take some of the deck apart, then build up a concrete edge that will keep the bricks stable.
OOPS, I “mis-overestimated” the amount of material I would need… another trip to Home Depot for a return. (I have loaded or unloaded these bricks 4 times now!)
Dasher was a big help! I think he likes his deck.