Module is not installed error

[Helga]

Hello everyone!
I need to have my own c++ module to be able to use it in .qml files. I create qml plugin (create project->library->qml plugin) with uri my_plugin. But when I try to install it (right click on project) that option is not available.
Then I create qml application and put put “import my_plugin 1.0” in main.qml. It’s not underlined red and it’s building without any warnings. But when I run it:
“Module my_plugin” is not installed.
I’ve tried qt example of c++ extantion timer and I cannot import their module as well. They say run

qmake
make
qmlscene -I import plugins.qml

But last two don’t work (can’t find make)
I try it on two different PCs. Result is exactly the same.
I’m sitting on this for 2-3 days and tried every recepi I found: some people complain on it - but topics s 2-3 years old, and solutions is not detailed enough for me to understand and perform right.
I’m pretty new at Qml and it seems I miss some simple details. Thanks in advance for ANY help.