Compiling external c++ source file

I want to use the google protobuf library which uses a lot of .h file and .cc file. I included the directory where the header file is but I don’t know what to do with the cc file.

I know they have to be compiled as well. I tried to add the cc file to where the build.cs file is in visual studio but it still gives me unsolved external symbols. How should i include those files correctly?

Thanks in advanced

I think you may have to compile it for each platform you are launching on and include the static compiled libraries via a plugin.