Use the slider to select warriors to go and help defend another village. The travel time indicated will always be based on the speed of the slowest unit. The warriors will be deployed when you tap the “Support” icon.
External warriors are listed separately in the troop overview of a village and, once they have arrived, they can be recalled at any time. It can be very useful to send warriors to other villages, for example, after capturing a village or in the event of an imminent attack.