The white pins of nodes are called execution pins. The other colored pins are the data pins. The execution of the nodes of a Blueprint starts with a red Event node, and then follows the white wire from left to right until it reaches the last node.

There are some nodes that control the flow of execution of the Blueprint. These nodes determine the execution path based on conditions. For example, the Branch node has two output execution pins named True and False. The execution pin that will be triggered depends on the Boolean value of the Condition input parameter. The following screenshot shows an example of the Branch node:

In this example, when Event BeginPlay fires, the Branch node evaluates the value of the Has Shield Boolean variable. If the value is True, then the True pin will be executed and will set the value to 100.0 in the Shield Value variable. If it is False, the value 0.0 will be set in the Shield Value variable.