There are two 5.5mm hex head screws holding the actuator in place, remove them and the actuator should come free. There may be some cables that you'll need to push out of the way to get the actuator out.

If you don't have a 5.5mm socket, 7/32" works well as an alternative. A 6mm socket may damage the heads of the bolts if you try to use it.

The third picture shows the old, original actuator (right) next to an aftermarket Dorman replacement.