With ambisonics, you record in First order (4 mics), or HOA (Higher order, >4 mics). The rest is math...
Look at ATK (Ambisonics Tool Kit) for starters. It's made for Reaper and it's free. In the ambi scene, most are using Reaper.
http://www.ambisonictoolkit.net/documentation/reaper/
I've wandered away from 8 speakers personally, because of practical restrictions of my room. But I won't even pretend I know what I'm doing
I'm still experimenting with my first ambisonic mic. It's DIY and isn't calibrated. I'm trying to figure out that part. It is however, nice to have around, as it saved my ass recently, when my main pair sounded dreadful.