You’re welcome.
This all depends on what devices you are using and how they are configured. All of your devices and I/O can be viewed in the Pro Tools “Hardware Setup” page.
If you are connecting 2 daisy chained devices to the 1st port of your HDX card, then the first device’s channel will be “A 1-16” and the 2nd device’s channels will be “B 1-16”. Examples of this can be seen here: https://cdn.eventideaudio.com/manuals/h9000/content/expansions/protools.html#integration
