I have no first hand experience with snowflakes, they're on my to-do list as something to try but I've never gotten around to it. Do you have extension tubes, teleconverter, closeup filters, etc. to get closer? With just a 1:1 macro, expect to do some heavy cropping with FF or an APS-C sensor. Max size you can expect for a snowflake is about 10mm, but those won't be super common and most will be smaller.
The links above show the two main approaches to lighting, either have the snowflake on glass and light the background, or have it on something black and position your light source in the front of the snowflake and use it to produce specular highlights in the snowflake (aka "Bright Field" and "Dark Field" setups you'd learn about as an exercise in photographing glassware).
I saw this fellow give a talk a few years ago, he uses a canon dslr, that 1-5x dedicated macro lens, extension tubes, TC, ring flash, handheld focus stacking, and more patience for this sort of thing than your average human:
https://skycrystals.ca/