red flag

Inactive players are attacking you because they are AIs and the AI decided to attack you.

The red flag with a travel line is to rally your troops to arrive somewhere at the same time. See below.

Thank you I am new to game

Rally points do not make your troops arrive at some same time, but make them go to the flag immediately after being produced. That way, if you produce a troop during the night, it will probably already be where you want it to be (for example at the front) when you wake up, instead of still being where it was produced and waiting for your orders.