That said I hope you find this Instructable easy and learn something about lasers.
Here is a video of the laser working:
Step 1: Parts List and Constructing Circuit
1x M140 Laser Diode : Found Here
1x Aixiz Module (not needed if you buy from above link) : Found Here
1x 445nm Collimating Lens : Found Here
1x LASER SAFETY GOGGLES (IMPORTANT) : Found Here
1x 100 OHM Pot
1x Standard Diode
1x 10uF capacitor
1x 1 Ohm 5W Resistor
1x Heatsink for LM350
1x Heatsink for Laser Diode : Found Here
Some switches or connectors (optional)
Once you get all of these parts put them together based on the schematic below.