Units in Strike Tactics are capable of following rally paths which are created by shift-clicking locations on the map.
Production buildings are also capable of setting rally paths, so that newly constructed units will travel along a rally path once complete.
Actions can be queued for workers by setting rally paths. For example, you can build 3 silos by shift-clicking the silo placement on the map.
By default, if a worker is busy building and you tell it to build another building, the building is added to its queue as a rally path. If you want a worker to stop working on building to do something else, you will need to manually move the unit (to cancel action of working on the building) and then give it the new action.