But let’s dig deeper so you can see what we mean.
The Planning Phase:

Here the game is paused. You can select each of your characters and give him or her a command (or multiple sequential commands). Typical commands are attack an enemy or move. Less typical commands include using items, healing comrades or ducking behind cover. If you would like to delay the actions of a particular character, you can even command him to wait until you want him to act.
At the bottom center of the screen, there is an Action Queue. Each box on the queue equals one second of real time. In this Action Queue, you can see the planned actions of each of your party members as well as how long it will take them to complete each action (measured in whole seconds).
The Action Phase:

When you have given all your orders, you can unpause the game and your party members will carry out those orders simultaneously. The enemy will also perform their actions. When you wish to give your party new commands or adjust their existing commands, you only have to pause the game.
So, control over your party members actions, timing your actions to take advantage of a situation... What does it all mean?
It can mean a lot of things as you explore different strategies and come up with your own tricks to beat the enemy. But here are a few examples:
Want to rush a guy with a rifle who is under cover? Have your party member wait (use the wait command) until he is reloading and then rush him.
Want to outflank an enemy but he has you pinned down? Take a quick peek at him and you can bet he’ll start firing away. When he is out of bullets, it’s time to make your move.
Want to save a party member from an axe-wielding madman? Send in a friend to give him a thump on the head. That should get his attention and he’ll turn on you.
Questions?