How to properly build a project in qtCreator?

Question

Qt

I came across a very interesting project, but under linux you need to build it yourself, and in Qt I'm not boom-boom.
https://github.com/barry-ran/QtScrcpy
It seems that I did everything as it is written
. I cloned the project into my daddy,
installed QtCreator and qmake,
opened all.pro in this very ide.
I press build und ales, an error flies in.

What did I do wrong, or what have I not done yet?