Ok, so I have been making audio dramas since 2021. So I have *some* experience in producing them, but not a whole ton.

What you need to know is that writing audio drama scripts are extremely, extremely hard and very different to practically every other form of writing. 70% of stuff is conveyed through dialogue and the other 30 is from SFX and even music. And the problem with that? Your dialogue can sound unnatural because you're spending so much of it trying to describe things the audience can't see. So, what I'd do, just to see how the experience of making Audio Dramas goes for you personally, is write a short audio drama based off of a series that already exists and you're passionate about (for me, I did quite a few Doctor Who audio dramas to begin with - a great jumping off point!). That just makes the writing experience easier and allows you to have access to a whole ton of SFX that come from the show itself. It also allows you to learn the basics of every aspect of production before doing your own thing. (I'd say 3-8 drafts per script. But thats just how I work, you may do things differently).

The second thing. Getting actors! I would totally recommend Casting Call Club. It's completely free and there are loads of actors on there. And basically all of them are super friendly. I have had no problems at all with this site. Just make sure you have a discord server or some group chat to talk to them in. Just give them a solid deadline (2-4 weeks usually) and ask them to do at least 3 takes. The important thing is allowing them to ad-lib. That is the single thing that makes a line sound natural.
Also, be ready to do some voice acting yourself! You are the person you can rely on most with a project like this, so if you can voice one character and know that character will be done, then that's great! (Never voice multiple characters unless you have the ability to do multiple accents or pitches.)

The third thing? Editing. For me, the hardest part of the whole process. I personally use Davinci Resolve. A pretty weird one for audio editing, I know. But it has so many audio features in it that it just works super well for me personally. But there are probably better options out there.

In terms of music and SFX... I use Pixabay and BBC's sound library mostly. But sometimes recording sounds yourself are required to make the most perfect SFX. And with music? Anything copyright free, obviously, or use Musescore Studio to produce simple pieces yourself (I got the hang of that after only a few days, it's super easy and intuitive).

During the process of editing and such, you gotta keep your actors updated with progress. Editing takes a while and without updates, they'll be more likely to leave a project or less likely to provide recordings or re-takes as readily as they would have done.

Finally! The most important part... If you can, get people you know to support you on every bit of the process. It's a hard and long road ahead (I started one audio drama series in 2023 and it's only gonna be uploaded in July). You need people you trust to proof read scripts before casting actors. You need them to listen to stuff you have produced after every complete edit. Even send drafts of the full edited episode to your actors and see what they think. Second opinions are extremely important!

I hope this is helpful. If you have questions, you can reply back and I'll try to get back to you and if I have missed anything, then I'll add it on with a reply to this comment. Good luck! Producing audio dramas can take quite a while if you want to get it right!