INSTALL.txt extension

I would like to install KDchart to develop an application with Qt Creator 15.0.1 and Qt 6.8.1. I am not an experienced developer and I can't figure
out how to install the application with only the INSTALL.txt file inside the repository. Is there a possibility to have a more detailed guide to install the software? I have CMake version 3.13 and QMake version 3.1 installed on my machine. Thank you.