for building- get all you need from forum members- many offer kits that are between cave-man eazy to advanced- start with low cost parts- many fail
with their first build. Find info in the tutorial section- especially those by DTR.
He offers some that are partially ready to use.. like pressed into the module for you or having the wires already soldered. Hosts with heatsinks are a good way to start.
buy from vets-
not newcomers so much.
Technically its sorta illegal to sell completed working lasers. But if you do the final assembly then thats OK. Very few build 532 Green handhelds-
exception now being the new diode greens 515 & 520nm-