Replacing a poorly placed light switch in my garage with a motion activated switch, and inside the box and existing connections are nothing like what the wiring diagram shows for the new one. The switch is in series but the connections aren't labeled on the back of the switch there now. It just has two black wires connected to it, one from a single cable which has three wires coming out of it (black white and ground) and the other black is to another pair of black wires that go to the other two cables that join the box. The single white wire is connected to the two white wires from the other two cables coming into the box. The new switch just has black, red, and green. Pictures below of current switch and box, new switch, and wiring diagram for new switch. Unfortunately, do not have a voltmeter handy...

Which black wire goes out to the light? That one will connect to the red wire. Black wire to the other black wire and green wire to the ground.

Got it connected but the light flickers in the auto setting. May be confused as it's in the corner of the garage, with a window nearby (works by temp change, not true motion detection). Mfg. says temp range is 32-122 F, but won't stay on fully when in auto mode. Works fine when switched to on. May just be a bad location for that type of sensor. I tried messing with the light sensitivity and time settings to see if that helped but no change. Oh well, lessons learned.