The presumably missing information regarding MADI...

Each MADI device receives the total number of audio channels from this MADI "bus" at its input.

On each MADI device which is connected to the same MADI bus you have to configure the routing once.

• which incoming MADI channels you want to route to which outputs on the device

• which inputs from the device you want to route to which MADI output channels

• all remaining MADI input channels (which you don't use at the device) have to be routed through, so that other MADI devices and the recording interface can receive audio from all channels completely.

You could connect multiple MADI devices serial, like e.g. 8 Octamic XTC:

+--Recording Device--->XTC#1---...--->XTC#8--+
|                                                                         |
+--------------------------<-----------------------------+

In your case, it is easy, as you seem to connect only one device to the MADI bus, then the routing is like this:

MADI IN---MADIface USB ---MADI OUT
|                                           |
|                                           |
|                              MADI Device Id #1---M1-16 IN---------->Analog 1..8 OUT (case 1, see list above)
|                                           |                  M1-16 OUT<--------Analog 1..16 IN  (case 2)
|                                           |                  M19-64OUT<-------MADI 19-64 IN    (case 3)
+----------------<---------------+

Once this basic setup is in place, you only need to route in TotalMix FX.