The protocol does not add peers, you will have to look for nearby ones yourself and add then in the config.
If you add more than one, you might start routing between those nodes. Probably Ok on desktop, not so much on mobile.
For next steps, it picks one 'main' peer for your outgoing traffic, based on speed. (once an hour).
On a higher level, the system builds a tree out of the peers that are connected and you send data from one node to the other by directions. Think "left at church, right at heardresser". Or in yggdrasil it is "Go to node 10, then from there to node 1, then to node 5, then to node 6".
In short; a tree is built based on the elected root sending out a package and which peer sends it to you first. Indicating that that is the fastest.
You send data the shortest route though the mesh using local directions only.
Actual traffic is encrypted for the destination peer, so other than some headers needed to route, everyone in the middle will just forward an unreadable blob.
