Laser LA03-5000 wiring to RAMPS 1.4 I'm totally lost. I have been searching about two days how to correctly wire Blue Laser LA03-5000 to RAMPS 1.4 board. 

This laser has 12&nbsp;V input and separates PWM/TTL wires. I have found out how to control laser with no PWM (just hook it to D9 same as a fan), but how do I correctly wire this type of laser? I really want to wire it correctly for safety reasons.
Please look into this question, this is a very similar question and also involves PWM and a RAMPS 1.4 shield. 

In your case you connect the top red wire on the right bottom connector to the D4 pin and adjust the firmware accordingly as described in this answer.

The bottom 2 wires of the lower right connector should be connected to ground and 12&nbsp;V (resp. black and red).