A group is indicated in design canvas by the group icon as shown below.
Inputs and outputs of steps within the group can be "exported" to the enclosing group by right clicking the input/output indicator of an enclosed step. This will make the input or output available to the enclosing group.
A set of steps can be converted into a group by selecting the steps (click-and-drag over desired steps), right clicking, and selecting "Create Group."
It is important to note that a group is a set of steps; therefore runs cannot be initiated on a group as runs are preformed for individual steps. Tasks can not be created for a group, only for the steps in the group.