How to attack and occupy resource plots in other states under dooms day contest?

During alliance wars (happens every few days during the doomsday event) you will be able to travel to another state to fight against another alliance. At this time you can place rally points in the other state to let you occupy plots and attack their structures.

If you keep some plots in the other state you can continue to travel there during the rest of the doomsday event and keep occupying more plots.