LMB
Place block
Click a tile to place the selected inventory block.
RMB
Block info / report
Right click a placed block to see who placed it and report if needed.
MMB
Pick block
Middle click a block on the map to select it in your inventory.
Drag
Move map
Hold any mouse button and move to pan the map.
R
Rotate block
Rotate the selected block 90° clockwise before placing it.
Wheel
Zoom
Scroll to zoom in or out.