How can I use a slider as header?

Step 1: Go to Appearance > Customize > Header > Header Slider.

Step 2: Select the desired slider from the Header Slider select box.

Before being able to set a header slider, you first need to create / import one from the Layer Slider or Revolution Slider tab.

Important: If you set-up a header slider, all header images will be overridden except the Individual Page Settings.