How should we know based on that little information. You even did not provided the error message.
The
QtMeshViewer class is not part of the Qt framework. Looks like it is from some kind of project. So you should check the related documentation and/or ask the people from where you got that.
The libraries are probably from the
OpenMesh[
^] project. If the error message is that the libraries can't be found you have to install them and adjust the path if they have been installed to a different directory and/or are installed with differnt file names (e.g. with version number).