Hey, pretty new to this myself but was able to set up a project. I haven't started mixing anything yet so I'm sure I'm overlooking things but hopefully, this gets you started.
Setup a new blank session and add an audio track (when you're creating the audio track you can select the output on that screen, then click to I/O and set to "quadraphonic") After that you can set the channel to surround mode and put a utility downmixer on the master. Then you will be able to insert the ambisonic b360 and NX to the chain.
Also, found this buried in the waves forum.. B360 Ambisonics Encoder – 5.1 to 4.0 and 7.1 to 4.0 are not supported by Logic Pro X. Honestly, I dont think this works right in Logic and waves support is 0 help. The manual states that you need to insert the b360 encoder on "each" track, but I have found no way to do so..