How to install Global Menu?

I want to install Global Menu same Mac OS but I dont know how to do
Please suggest me.
I found appmenu-qt5 but I dont know how to using it. Please help
Thank you

You can’t.
It hasn’t been ported to Plasma5 (yet).

See also:

But apparently for KDE applications to support this at all you need Qt 5.7 at least anyway (which hasn’t been released yet)…

Global Menu Applet

Yes, that’s right. I recently had a look at the Global Menu stuff we get asked for a lot and I managed to write a working, albeit ugly, prototype. At the moment its use is quite limited, as the only application I could find that makes use of it was Chromium.]( 5 Global Menu Applet showing Chromium’s menus

The good news is that there’s an ongoing effort to upstream support for it into Qt which means all KDE and Qt applications will eventually support this! The bad news is that Gnome uses their own thing, GMenuModel, whose DBus interface is deemed non-stable, so we can’t really support it. Furthermore, it looks like Unity will also use GMenuModel instead. Also, it will take quite a while for the Qt version with support for it (I hope 5.7) to be widely adopted, so you’ll need to wait at least another half a year, probably more, for this.