When you get sources you generally get a lot of files. Some or most could be readable by some means. In some tarballs you may get pre-compiled bits and pieces.
It also may have some legal files like who made it and how one can use it and copy it. Other files may be notes on how to make it. Some sources may need many many other programs to get it working and may also need many other packages to assist the final program. Every once in a while one can use a wysiwyg or graphic type of building app.
So, let me first say, what are you really trying to do? Do you want to make the program or look at editing the features?
To answer your question. Sort the 1000 or so files into extension ending sort. Search online for what each extension may mean. Generally this will be common. For example. http://stackoverflow.com/questions/1...ions-mean-to-c
In those groups you will find out how to use them. Some may have no meaning on your build too.
On that link you will notice too that the language of the tar will have to be known too.