...I really don't need the zenier diode? plan is the zenier and 100 ohm resistor?
Did you ever watch the video on the hackaday page I linked to in post #12 of your other thread?
It explains everything.
To go back to that thread, you show a schematic with a STN3P6F6 P-chan 60V 3A sot-223 device, a 12V zener (not sure of the P/N), and a 100 ohm resistor.
The STN3P6F6 has a Vgs rating of +/-20V, so unless you plan on having a DC input > 20V you don't need the zener (and resistor) with that part. That's a hefty part, and would work for just about anything up to 15VIN, but it's probably overkill.
The Si2301 has a Vgs rating of +/-8V, so as long as you don't plan on using a DC input > 8V you don't need the zener (and resistor) with that part either.
If you DO want a larger input range then you'll want a zener (and resistor), but NOT a 12V one... maybe 5V-6V. Again, the video explains all this.
The Si2301 is in a different package type than your original schematic (SOT-23 vs a SOT-223), so watch out for that.
If/when you redo the schematic pay attention to which pins are which (D-S-G). Connect VIN to the Drain, Output to the Source, and "GND" to the Gate.
It is important to wire it "backwards" of how you would normally use it so that under normal operation the D-S body diode is forward-biased and conducts.