The rubber band feature is the ability to select multiple components in the layout editor and manipulating them at the same time. You can select multiple components by clicking and dragging over those desired pieces, use Shift + Click to multi-select components, or expand the components menu to the left of the grid and select components there. Once selected, manipulate as necessary using the Properties and States menu on the right.
There is also specific documentation about what can be done with the components if you visit the User Guide under the Help tab in your account.
Hope this helps!