Some online discussions and AAR's give the impression that leader activation and movement occurs cyclically: activate, move, activate, move. This is incorrect, as note by the game's designer, Roger Miller:
All leaders are activated in the command phase. This is before the movement phase and the rolling of MP's. This is deliberate to show that an operation required that orders be sent out, supplies coordinated, etc. before anyone starts marching. Allowing some leaders to not be activated after a poor movement die roll is more the age of radios
So you must conduct your turn in the following order:
1. Spend all the activation points that you wish to in the command phase to establish your command structure for the turn. Also note which units will activate as a group, since all member of a group use the leadership rating of the activating leader on the Movement Matrix.
2. Conduct movement and hasty/normal attacks. Move leaders (or groups) in the order of your choice.
3. Day turns only. Individual leader initiative. You may attempt to activate one leader under his own initiative (provided he did not activate in step 1).
4. Prepared attacks are resolved.