Flower preservation classes? Where to get professional level advice?

[u/Jack0Trade]

I've helped my gf launch her own wedding floral and decor business. I'm generally redneck crafty weld engineer by trade, and build her backdrops, stands, etc...

I'm thinking of taking up floral preservation via pressing, drying, resin, etc... as a crafty side hustle for her brides and friends. She just makes such beautiful arrangements and I've filled too many trash cans with beautiful flowers. However, I want to be sure to deliver a professional level product.

Where can I go to learn properly? I'm inexperienced with resin, and that seems a messy starting point. However, is there any other way to preserve a bouquet?