how i use in multiplayer in unity

How to use Unity Multiplayer Networking software

and how i use in multiplayer

 

there is no such thing as "multiplayer software"

Unity has networking present to create a multiplayer game but you must do that yourself.

The network example in the resource section of the website + the network zero to hero guide on the board here + the documentation on networking should get you going.

 

how i do that alone in dlls c++ in the version pro?

 

Unsure what your question is targeted at but: C++ libraries allow you to add new functionality to standalone application builds.
You can not use C++ libraries to control any aspect of unity though.

 

i can explanation how to use in multi player in unity?

 

See the networking example here as well as the documentation in the manual, reference and script reference on Network