I'm really happy that you are interested in my Composer Toolbox app. This receiver is a middleman between Composer Toolbox app (on your mobile device) and DAW (Digital Audio Workstation) on your PC.
Before using this, you need also a virtual MIDI port (I recommend loopMIDI) on your PC, so you could set it as "Output" here, and as "Input" in your DAW, so it will let both of them to communicate with each other. When it's ready, refresh this page and click "Host" button above. You will be assigned a 4-digit number, which you use in Composer Toolbox App in the right place, connecting those two. When you have your Output/Input ports set properly and connected app with receiver, you are ready to use the app wirelessy, unless you close app or this page (when you disconnect either way, you need to refresh both app and receiver and connect them again).
If you encounter any problems with using this software or want to send some suggestions, words of gratitude, you are free to contact me throught in any way listed on this page: https://krylan.ovh/portfolio/en/contact