On their turn, each player must play 1 Action card from their hand onto the desk on their Study board, and they may, if they wish, perform any number of Quick actions. Quick Actions can be performed in any order: Before, During, or After a Basic Action.
Every Action card has a Basic Action Symbol in its lower half, and may or may not have a Special Effect symbol in its upper half.
To play an Action card take it from your hand and place it on your desk in the first available space from left to right. Then perform the Basic Action and apply the Special Effect if there is one. If you wish, you can decide not to perform the basic action and/or not to apply the special effect.
The value of a Basic Action is the same as the total number of symbols of that same particular action that are visible on your desk, including the one on the Action card that you have just played.