We currently don't include a provision to name a temporary Guardian. This is because temporary Guardians are only used in some states, and they're often not as beneficial as they might seem. It usually takes a few days to have the temporary Guardian appointed, by which time the permanent Guardian will have had time to arrive in your state, or to the U.S.
In that interim period, the child is typically placed with local family or family friends. A child may also be placed with one of the backup Guardians you've nominated until the primary Guardian is available to take over.