how append menu into rhino?
There is no special code to do this, just use the Workspace Layout manager from the Tools menu. You can make new buttons and new menu items that call a script, and in that script you can call any command(s) you want, including commands from your plug-in.
If you put your buttons, icons, menu items and scripts into a separate RUI file, this RUI file can be deployed together with your plug-in. If you put it in the same directory and give it the same name as the plug-in (except the extension of course) Rhino will automatically load it for you.