Darucas: Try throwing/putting down some rocks, until the plate is activated. You may have also found a stone amulet, which looks like a blocky rock in your inventory. It creates the same kind of block you have destroyed - place one amulet in one hand, exit inventory, click on the amulet from the interface when you're in front of the plate.
If you just want to move a block, just walk into it.

Hope this helps!

Keep some rocks and as much stone amulets as you can though, it's always helpful later on.

BelatedGamer: You click on your characters face, and then the icon that looks like a floppy disk.