You could have your Mom do a search of forum / web for laser Arduino connection.
Have her get you set of protective eyewear
so next post is NOT --- looking for white cane
I don't understand the 12V -- 5V board ---- there is 5v available on RAMPS or arduino
and power supply to laser board doesn't supply 5v
Why not get 12V from 11A or 6A
better supply independent 12V from wall wart to barrel connector on laser board
then you may not need 5v converter ??? How much current does laser draw??
What laser type / supplier.
the supplier doesn't provide wiring diagram
Can't read text on your photo?
Laser needs:
Supply to laser supply 12V 12v controlled down to supply 3.3V for diode
trigger on laser supply board to turn laser ON/OFF ---- if TTL apply 5-12 v for ON remove for OFF
??? Do you want to PWM your laser (pulse width modulation)
??? What software / firmware will you be using --- what does it prefer for laser trigger
----- D9 or pin on arduino
Perhaps a look at
ttps://jtechphotonics.com/?page_id=1503
Good Luck