Welcome to the forum.
Thank you so much for the information. I didn't know if it was okay to plug a TTL line into a PWM port. What is the benefit of the temperature module if any?I'll take a stab at this, but I will repeat that I am not familiar with your particular laser.
Some of this you already know. The power supply plugs into the temp/control module. Then from that module, you use the 4 conductor wire to connect the module to the laser.
Now, you need to connect the temp/controller module to your cnc controller. You only need 2 conductors to do this - pwm/ttl and ground. I understand that your cnc controller board (woodpecker v.3??) has a 3-pin output. So, I would simply plug in a 3-pin plug, with only 2 conductors running from it - one each to pwm and ground. You don't need the 12v since you are getting that from the temp/controller board. Make sure you respect polarity.
If your cnc controller is outputting pwm signals, when you turn everything on, there should be no light coming from the laser. It is waiting for a pwm signal to set the laser's strength.
Unfortunately, I am not familiar with lasergrbl either. I use Lightburn. The basics, though, are that you must set laser mode in your grbl controller to "on" and you must set a maximum "speed", which is translated to power on the laser. A recommended speed/power is 1000. Then in your laser software, you set the max speed to the same 1000. That way, when you set power in your laser software for a specific project, it is a percentage of the max = 1000, and the max is the same in your software and in grbl.
I went ahead and bypassed the temp module and it works great. I was expecting a few hiccups but it lit right up, ran a test file and there seems to be full power level control. Let the fun begin. Thank you for your help with this, it's much appreciated.FWIW, I would think that you're correct.