Using and Creating New Groups:

Groups are sets of tiles that are related. Clicking on a group's "parent" tile will cause the "children" tiles to be displayed. A group is created by dragging an existing tile and "snapping" it to another tile. This creates the "parent/child" relationship.

Moving / Snapping a tile : Hold the SHIFT Key and press the Left mouse button on the tile, then move the tile over the desktop (it will snap automatically - horizontal / vertical) to another tile when approaching the Snap distance (defined in HVD config / Dock creation)

NOTE 1 : You can move an open/closed group and snap it to another tile/group (with the SHIFT key)

NOTE 2 : You can check the option "Show Group indicator" in HVD config panel in order to see which tile is a group.

NOTE 3: You can force Hoverdesk to keep groups that are not part of the main dock open at all times, by checking the option in the HVD Configuration / Theme Creation tab. (Misc Options/Don't close groups)