Thanks for your guidance. Here is what I’ve done so far, but not working… 
Any help diagnosing would be much appreciated:
So on the connector that came with my PMS7003, the connections are a bit different to the data sheet. Goes from 10 pins down to 8 through the connector. See below:
I’ve connected it up to my breadboard, Electron as follows. Pretend PMS7003 is connected to the generic header in diagram.
In the Fritzing above, used a header where pins 1-8 align with pins 1-8 on the PMS7003 connector (as per first photo).
I’ve then used @MartyMacGyver’s code - adding the following to try and pull SET high:
pinMode(D3, OUTPUT);
digitalWrite(D3, HIGH);
I suspect this is completely wrong, and have no idea how to pull RESET high. Tried doing a quick search but couldn’t find much on how to do this. Should pulling have been done through hardware?
Also, is there any code missing from @MartyMacGyver’s repository? I would have expected to see normal stuff like defining pins etc - like I’ve tried to do above? Am I missing something?
When viewing serial output, I’m just getting:
-- Initializing...
-- Reading PMS7003
And nothing else.
Thanks!
Matt