Endurance provides a full guide book about laser connection.
In this PDF file you may find and learn about basic principles of laser connection.
Before connecting the laser please read manual of you controller (mother) board first.
All controller (main) boards have power output for fans, lasers, spindles, etc..
You need to find 12V output and a ground.
If you already found 12V output – make sure that I has enough amperage capacity. For different types of lasers you need different amperage. You may require from 2 up to 6 amps capacity.
Never connect the laser if there is only 12V and 1A output o less. That will simply burn this output.
If the laser you choose requires more power then you have, then you need Endurance MO1 PCB.
If you want to use TTL to turn on / off the laser – it should be connected to PWM output. Usually it is 0-12V output (does not matter)
If you do not have PWM (like most 3D printers), simply connect TTL (small wire) with 12V+ (the same output that goes to the laser)