Adding a Resource group to a resource is optional.
Resource groups can be used as a planning option within both Graphical plan boards (change Settings on the plan board to plan by resource group).
A resource's link to a resource group can optionally have an expiration date setup.
Steps
Go to Work order project planning > Resources > Resources.
In the list, find and select the desired resource.
Click Add.
In the Resource group field, enter or select a value.
In the Expiration field, enter a date and time.
Click Save.