The tool axis is will be tilted from the surface normal direction towards the tilt axis. The tilt axis can be the X, Y and Z axis or any line created in the geometry. Imaging that tilt axis and surface normal span a plane. Only on this plane the tool can tilt.
In this case the Z axis is the tilt axis. So the tool tilts with a 45 degrees angle from the surface normal against the tilt axis.
Fixed tilt angle
This angle value describes how much the tool axis direction should be tilted from the defined tilt axis direction. In other words, imagine a plane spanned by the surface normal and the tilt axis. The tool direction vector will rotate on this plane from the tilt axis direction to the surface normal direction about the fixed tilt angle.
Tool axis crosses tilt axis
If the switch tool axis crosses tilt axis is set to true, then it is enforced, that extension of the tool axis direction is intersecting with the defined tilt axis.
Reverse tool
If this switch is set to true, then the tool direction is reversed. E.g. if reverse tool is set to false, then the outer of cylinder is machined. If reverse tool is set to true, then the inner of cylinder is machined.