Found the answer in a much older post but I'll add one here for the record.

1 - Disconnect Vacuum cable.

2 - Press down forcefully on the locking tab and hold. It is located between 12 and 1 o'clock on the actuator on the far side of the assembly.

3 - Pull the assembly towards you firmly. No twisting or rotation is needed.

4 - Simply slip the new actuator into the slot. It requires little force. The locking tab will click into place indicating sucess.

5 - Re insert Vacuum cable.