FOA in A-format

The different microphone systems have their own advantages, but what is common for (almost) all of them, they record in the so called "Ambisonic A-format".

There is no universal "Ambisonic A-format", but there are many of them. An "Ambisonic A-format" is directly connected to the ambisonic microphone system you are currently using.

There are many plug-ins out there to convert such recordings into the "Ambisonic B-format", a international valid format for Ambisonic recordings, resp. the order of  the channels or such a recording.
The first channel carries the amplitude information of the signal, while the other channels determine the directionality through phase relationships between each other.  B-Format tracks contain a speaker-independent representation of a sound field.

This means, that once you have recorded your sounds with a certain microphone system, you have to render it in your DAW with matching plug-ins, to get the desired amount of tracks, containing the speaker-independent representation of the sound field you recorded.

In the case of First Order Ambisonic (FOA), there will be four tracks, named "W", "Y", "Z", "X" (if it follows the AmbiX convention). If you use microphone systems with higher order of ambisonic, there will be more channels.