Well that’s a loaded question with 3 answers (that I know about).
1- check here for some discussion about the current efforts to improve the openhab native plugin. Check here for some discussion about how to install the latest development homekit version.
2- check here for a tutorial I put together a while ago about using node red to “expand” homekit abilities. Note I was not the first (nor last) to use this setup, check here for some other examples.
3- If you’re a fan of NodeJS then you can use this homebridge plugin to connect to homekit
Welcome to the community! There is a lot to learn… Option 1 above is nice because it is “native openhab” and keeps everything together. Option 2 is what I’ve used in my house for the last 9 months or so, works great. Option 3 should also work great, I’ve never used homebridge with openhab but I have used homebridge and it does indeed work great.
Good luck!