how to include libraries and header file needed in github project?

very sorry if this is a dumb question , i was trying to contribute to open source project kiwix desktop for the first time , its made using qt framework (https://github.com/kiwix/kiwix-desktop).

while trying to build in visual studio it shows many header files missing , i found those header files here (https://github.com/kiwix/kiwix-lib/).I simply downloaded the header files and added it to my include directory , but this caused new errors as it required other .cpp files too

Now i dont know how to include them. please help me install this https://github.com/kiwix/kiwix-lib/ , thanks in advance.