Cults (how to do them right???)

one of my playable characters is a priest in a cult and I've never really done anything like this before. all I have right now is what the cult is called and who they worship (and what they do ofc) but I don't know how to incorporate that in game imma be so fr other than the regular priestly things (like prayers and stuff)...help from the pros (or literally anyone because I'm stuck)

It depends on if you want to do a fantasy cult or a irl one. The most obvious aspects is what they do in their daily lives, what they believe in and why they are in the cult. With fantasy cults, they usually want to help some kind of horrifying being gain power for one reason or another, you could try flesh it out. If you want to do realistic cults, they are often centered around isolation, preventing people from owning anything & love bombing them so they become dependent on the cult.

So, lets cover what you mean by "a cult"; the above post covers the two main tropes associated with the term, but in point of fact the term can cover a lot. One common example is a "mystery cult"- basically an organization/faith that conceals its beliefs and practices from outsiders. This can play into the two given examples, but it can also be entirely benign- the Freemasons fit the general theme, having an organizational structure, ceremonies, etc. that they don't make public. Or really any new/removed from the mainstream belief system can be classified as a "cult".

You're talking about this like the role has been handed out to you rather than one you chose for yourself. If this is something your DM or someone else has come up with, best bet is to ask them for more details on the background.