MOKO LW004-PB Downlink and Fport

If anyone can help me understand the downlink process of this device I will be immensely grateful.
I can’t find information about DownLink Port (Fport) on the user manuals.
And even payload information is confusing.
Uplink is happening normally, and I am studying the decoding shown at the link: (
Thank you very much.

I don’t understand “Page 404”

Finally discovered: Fport (TTN downlink page) to V3 is port 100 and payload need be as the described on V3 manual