Assume that you didn't changed the buildDir variable in the project's build.gradle file, so your build directory is at C:\ApertusVR\build\android. Now if you successfully built the project, then you should have directories there like: C:\ApertusVR\build\android\ApertusVR\apertusvr\intermediates\cmake\debug\obj\<abi>. Where <abi> is one of the three supported ABIs (arm64-v8a, armeabi-v7a, x86). In those folders there are several *.so files. To be able to debug native code, we will tell Android Studio, that it can find these libraries there to fill its symbol table for debugging.