3 wire laser connection to RAMPS 1.4 - assistance please (2 replies)

Hi All.
I've built a MPCNC and I planning on mounting a laser module so I can cut and engrave.
The controller is an Arduino mega2560 with a RAMPS 1.4 sat on top
I'm currently running Marlin 2.0.9

The laser is a 12v 10W (80w according to the listing [www.ebay.co.uk]) with an
Input interface:XH2.54-3Pin (+,-, PWM/TTL)

This is a red, white and yellow cable.
If I connect the red and white wires to the Fan output (D9) I can vary the speed that the fan on the laser is running with M106 s(1-255) but there is no laser light.
When I connected the red and white to the 12v input cable and then connected to yellow to a 5v pin the laser comes on so I've proven the laser worked (one of my main concerns)

I'm just a little out of my depth with the config of marlin.
according to [marlinfw.org]
I need to enable LASER_FEATURE in Configuration_adv.h - DONE

Then I get a little lost as the docs branch out with standard, inline, dynamic inline and trapiziod modes and power.

Can anyone decode this voodoo for a layman who wishes to learn, perhaps with a single set of clear instructions regarding what I need to connect where and what needs to be in the config to make it work?

Any help and advice is greatly received - many thanks in advance.

W