Default select

Left-click on a unit to change your selection to that unit. Selecting a unit will deslect all other units. Left-click anywhere on the map to deselect all units.

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Selection Box

Left-click and drag to draw a selection box.
All units within the white border will become your selection. Again, use shift to avoid deselecting your previous selection.

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Add to selection

Hold shift to add units to your existing selection, without deselecting what you already have selected.

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Remove from selection

Hold control to remove units from your selection, either by clicking or dragging.

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