Please Help Wiring Switch


So I got a Simply Automated US11-40 switch to control an outside light...however there's more wires on that switch than on my regular, original switch...
My switches all only have a Black and Red wire (and a green ground) attached to it...
Please see picture:
Left switch controls an outlet somewhere, middle switch controls the outside light (the one I want to replace), right switch controls an inside light that I may or may not want to replace with a SA switch later)...
I think there's some white wiring wing-nutted (did I just say nutted?) to some wiring...hard to tell with all the texture spray, but no white wiring connected to switches...
The old switch only switches the "hot" wire in order to turn the light on and off.  The SA switch has additional wires because it needs a connection to the white neutral wire and possibly to other switches for this light, if this were a 3-way switch circuit.
In your case, you need to determine which wire is the hot wire (probably the black) and which wire goes to the light (probably the red).  Use a voltmeter to do this.
Connect the white wire from the SA switch to the other white wires in the wire nut bundle.  Connect the black wire from the SA switch to the black wire that goes to the old switch (assuming it is the hot wire). Connect the brown wire from the SA switch to the red wire (assuming that is the wire that goes to the light).  Leave the brown/white wire unconnected, but cap it off with a small wire nut and tape to secure it.  And also connect the bare ground wire from the SA switch to the green ground wire in the box.
Cool that's what I thought. Now if I use other SA switched in the same box can they share the same neutral?
The switch neutral should connect to the neutral that goes with the hot wire for the circuit being switched.  It's difficult to tell from your picture, but it looks like all the neutrals are in one wire nut bundle.  So in that case, yes, you would connect both SA switch neutrals to the one neutral bundle.