Complete beginner at astrophotography. Where do I even start?

Hey everyone,

I've been wanting to try astrophotography ofr a while but I genuinely have no idea where to begin. I'm looking for practical advice on the full workflow: shooting, settings, and post-processing.

My gear atm:

• Fujifilm X-T5
• Rokinon 135mm f/2
• Viltrox AF 56mm f/1.2 Pro
• A tripod (no star tracker)

(I have other lens but mostly short focal, I guess you don't make astophoto with a fisheye)

What I have going for me: I live in rural France with very dark, clear skies, so light pollution isn't really an issue. And I can stay up late at night without any issue.

What I'd like to know:

• What settings should I start with? (ISO, shutter speed, aperture) I've seen people mention the 500 rule but I'm not sure how it applies to a crop sensor.
• Which of my two lenses would you recommend starting with? The Rokinon seems great for detail but I'm guessing star trailing becomes a problem fast without a tracker.
• How many exposures should I be stacking, and does it even make sense to stack without a tracker?
• For RAW processing, what software do people actually use? I've seen DeepSkyStacker, Siril, Sequator thrown around but I have no idea what the workflow looks like from card to final image. (For reference my usual post-processing software is DXO)
• Any beginner mistakes I should know about before I go out and freeze for three hours for nothing?

Appreciate any help. Happy to share results once I give it a shot.