Once you enable the 3D option, the 3D Rotate tool becomes available and you will see a rotation sphere appear around the pivot points indicating the different axes.
You can click on the direction ellipses to rotate your layer on one axis only. If you click anywhere else, the layer rotates freely on two axes at once. Once the ellipse is selected, it will turn pink.
|•||3D Translate Tool|
|•||3D Scale Tool|
|•||3D Transform Tool|