Oh yup they sure do ;)
It's fun to watch them if you can catch it. They open and close and wiggle a little to adjust the slightest hahah but overnight can move A LOT! They like rocks over sand but be careful placing them on rocks too high as they could walk off. I made a clam "nest" where I wanted them out of little pieces of my rock so if they do move they dont fall off. They will climb so watch out for that as well!
If you have your Maxima on the sand try to put a flat piece of rock under it so it has something solid to attach to.
Maximas also like A LOT of light so put them in a PAR at least 250 but as high as you can give them would be best.
With the right amount of light and a little phyto/oyster/reefroids depending on size you will really grow a Clam pretty fast ;)