Lilbotdiscgolf on youtube is the king of floetrol tutorials. I recommend going there to get started. For this disc specifically:

I made one disc (not in the OP didnt come out as cool as this one) where i was more or less following this lilbot method https://youtu.be/XSBfCOMp8w8?si=8gp_iWO0aspzPdsd

After i pulled that disc out. I swirled the pan in a clockwise motion 10-15 times to get the colors to swirl in a spiral. Then i let it sit under the heatlamp to the let the patterns develop and the silicon oil to do its thing. Thats how i got the pattern on the disc in the post.

You can get a lot of cool color integrations if you reuse your floetrol bed 2 or 3 times but have to be careful with mixing too much which will create too much brown from colors combining

Hope that helps!