The basic Idea of the implemented Multiplayer is, that the
server does all logic and calculations (such as Movement)
and sends the important data to the clients. (like the
position, pan,etc)

The clients on the other hand usually only send commands to the
server via send_skill or send_var.

(look up these functions in the manual)

The server either reachts on changes to these commands using
a server event or comparing it with the previous state.
Then the logic of the entity action on the server does the
game-dodo and for example moves the entity.

Changes are (on default) automatically send to the client,
wich sutomatically moves the entity or updates skills.

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If you like to have the client have more control, you can
change some setups to manually exchange data between client and server,
or let the server send updates to specific clients.
Here it gets tricky, and cant be explained in short.

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The "syncronous simulation" you mentioned is not
the default concept, but can be reached with workarounds.
For it to work properly, you need to keep a very
close eye on the way gamelogic is calculated, to keep
it fully syncronous on all clients.
using physics is not the best idea in such a system,
as it will most likely give different result on
different client, wich multiply quickly.