I would highly recommend doing a tincture!

For 6 oz of extract, usually enough for 10 gallons depending on spice level, use 6 oz Vodka (something decent, but not too expensive) add in your peppers (I like extra spicy so I think last time I did like 6? Habaneros In the jar) and shake every now and then for about 4 days. Strain out the peppers and toss the jar in the freezer. If there’s any crud at the top that froze over scoop it out and toss it. Then add that to your beer.

I prefer using tinctures since it gives you a lot more control, what I’ll do is pour 1-2 oz of beer into a glass and add in a few ml of the tincture. (Mixing imperial and metric units, I know) until I find the spice level I like. Once I know how many ml for 1-2oz of beer I’ll extrapolate that out and do math for a 640oz (5gal) batch and add that much in to my keg. I like this method since it gives you a lot more control and repeatability than just tossing peppers into secondary (some might be super spicy some might be duds, etc). One other thing: I don’t know if I’m crazy and I’ve wanted to test it but I’ve been busy, I find dehydrated peppers add in more heat than fresh peppers, not sure why though, maybe it’s just in my head lol.