When the very first Mackie Control button is created, you must select the layout you want to use and which midi ports to use. If needed you can change these settings later, but assuming that these settings hardly ever change, the settings are tucked away under the Layout and Midi ports arrow at the bottom of the editor area.
The right side of a physical Mackie Control contain switches that can be assigned to daw specific functions. The Mackie has printed labels for these buttons but there are lexan overlays that can be placed on the Mackie to display labels for specific daws.
Select the Midi ports that should be used for communicating with your daw. All Stream Deck Mackie Control buttons will use the same midi ports. If you later change the ports for one button, all other buttons (using the Mackie Control action) will automatically adapt to the new ports.
Please note that the Mackie Control protocol requires that the midi ports used in the communication are exclusively dedicated to the Mackie Control. In your DAW, the used Midi ports must not be connected to anything else than to the Mackie Control receiver.
Please check the website for more details.