@Nnady, the whole point of the Boron is to act as a Mesh gateway, giving mesh nodes access to the cloud/internet. The Boron has an Nordic nRF52840 MCU which provides the Mesh connectivity via OpenThread and a Ublox LTE CAT-M1 modem for providing cellular connectivity. You seem to be stuck on the BLE Mesh which IS NOT USED in Particle Mesh devices. Think Zigbee protocol “like” instead!
The Mesh is formed between the Boron and other Mesh nodes, typically Xenons. These are registered on the Particle Cloud for billing purposes but the Cloud is not part of the Mesh itself. With a Boron (or Argon) gateway, Mesh connected devices can access Cloud functions and be accessible via the Cloud. A gateway also allows Mesh nodes to perform direct UDP communications to the internet (but not TCP).
Without a gateway, Mesh communications still function with Mesh nodes able to use Mesh-only publish/subscribe communications (over UDP) making node-to-node connectivity very simple.
Perhaps explaining what you are trying to achieve would allow us to better steer you in the Particle world.