Cannot select Qt version in Desktop Kit

[CaseB]

In the past I worked with qt5 on Windows. Now I want to install qt on Linux Mint (version 21 with xfce).
I download and run the installation file. No problems and qt creator version 9.0.0 is installed.
When I create a empty QtWidgets Application QT create says 'no suitable kits found'. I had this problem on Windows too. In the kit 'Desktop' I can't select a Qt version.
So I go in the menu to Edit, Preferences, tab QtVersions. Qt Creator can't find qmake. So I click on Manual, Link with Qt. It suggests:
/home/kees/Qt/Tools/QtCreator/share/qtcreator/. If I click on Link with Qt, no error, restart qtCreator and nothing changed. I still can't set the version in
Do I have to install qmake seperatly? And how do I do that?

[cristian-adam]

Link with Qt... should be done with something like /home/kees/Qt since this is actually Link with Qt installation.

This is meant to find all Qt versions and not just one.

But, you can add Qt one by one by clicking Add... and searching for the qmake or qtpaths executable.

See https://doc.qt.io/qtcreator/creator-project-qmake.html for more details.

[CaseB]

The problem is that I can't any qmake version. Where is qmake installed?
In /home/kees I did:
find . -name qmake
./Qt/Tools/QtCreator/share/qtcreator/templates/wizards/projects/qmake
./Qt/Tools/QtDesignStudio/qt5_design_studio_reduced_version/bin/qmake
./Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/bin/qmake
./Qt/Tools/QtDesignStudio/share/qtcreator/templates/wizards/projects/qmake

and
find . -name qtpaths
./Qt/Tools/QtDesignStudio/qt5_design_studio_reduced_version/bin/qtpaths
./Qt/Tools/QtDesignStudio/qt6_design_studio_reduced_version/bin/qtpaths

To which path should I point qmake for the new version? I tried a few, but the font for the path turns red and after restart nothing happened.

[JoeCFD]

Qt is not installed. It looks like only qt creator is installed. On linux to check where qmake is used, type:.
which qmake
or
locate qmake
find is also ok.

[CaseB]

@JoeCFD
Thanks. There is no qt installed, just Qt creator.