Groups themselves are not content, but contain steps, can be conditionally enabled.
Group labels are not shown to users, unless you choose to show them within the progress bar.
If you do not define groups, all steps appear within a default group. The steps within this group will always be shown at the end of the flow.
To add a group, click Edit groups when hovering the left-side groups editor, or click the arrow at the top right.
In the expanded group editor, you can add groups and then create steps within them.
If you want to move existing steps into a group, you can drag them into groups while the group editor is expanded. Alternatively, you can use cut and paste to re-organize content between groups.
Groups can be made conditional, which will show or hide all the steps within a group all at once.
Group style overrides can be used to alter any part of a style set within a group.
These are particularly handy if you have distinct sections of a flow which might want to adopt a slightly different look-and-feel. For example, you might have an Introduction group that contains some lightweight questions and content perhaps a more colorful and spacious design. You can follow that with a Data collection group that has a denser layout to facilitate answering many questions all together
If you enable it, the progress bar can display progress on the group level rather than the step level, which can help responders place themselves within a longer process.