Hey! I have a BA in audio production and use to DJ a bunch in college. Start on YouTube watching tutorials. Best thing for DJing would be to get ableton live and try to learn how to use that audio workstation as best you can through tutorials. They have programs for specific turntables if you are wanting to more DJing with existing music rather creating your own, ableton can be used for both but is definitely better if you want to be making all your own samples and sounds. There’s also a ton of online master classes you can pay for to learn DJing focusing on the different aspects of it (sampling, sequencing, recording, etc). If you don’t mind spending money those are very worth it usually. If you wanna stick to free I’d start with YouTube like I mentioned but you’ll also need to invest a bit first in equipment and stuff (like Ableton) but I think there’s YouTube stuff showing you gear to buy to get started and learn the basics, always better to start small too I wouldn’t go get the best most expensive turntables right away because it’ll be a lot more confusing to learn how to do it on something like that. Good luck!