It’s a little vague anon, but that’s okay.
Firstmost, I would start by telling you that in Hellenic Polytheism, Dionysos wouldn’t be your patron unless His spheres of influence encompassed you work or where you live (ie. you were a brewer vintner, sommelier, involved in theatre or the arts in some way, bartender, club owner, mental health clinician, lived on Mt. Nysa or the island of Naxos, etc. etc.), rather you are looking to say you want to be His devotee. I get an ask like this one every few months, so you really aren’t alone.
Secondmost, There’s two places to start, and starting them in conjunction is probaby for the best. First: dive right into worship. Just go for it. If He calls to you in any way, answer that call and see where it leads. Second: research, research, research. If nothing else, research the basic ritual and offering structures of Hellenismos so you know you’re doing it in a way that He historically accepts, and research His myths and nature more. Eventually you can branch out into broader philosophical, mythological, etc texts, but Big D alone can give you years of study!
Thirdmost, If you want a super quick primer, here’s the quick and dirty:
Offer wine, fruit, flowers, fresh potable water, incense, or dancing after ritually purifying yourself and focusing yourself on the task of worship. Start with Homeric and Orphic hymns, The Bacchae, The Frogs, and His other mythos, and the scholarly works around them. Give. Give and give and give.