Drag the pointer over the villagers, military units, or boats you want to group. Or hold down the CTRL key and click each unit.
Select a group (as described above), then click the Group button. When you click one member of the group, the other members are also selected.
Click a member of the group, and then click the Ungroup button.
1) Select a group.
2) Press CTRL and the number to assign to the group. For example, to assign the number 2 to a group, press CTRL+2. The number appears in the lower-left corner of each unit in the group.
3) To select the group, press the number assigned to it. For example, to select group 2, press the 2 key.