Linking the socket library in xcode???

Help, please. I have an assignment for school that uses socket programming in C/C++. I have my code written, but my teacher is telling me that I need to link the socket library into my program to get rid of these errors. I have all the #include statements that are needed, but I have no idea how to link the socket library in xcode. The teacher doesn't know either, since they use visual studio. Any help would be greatly appreciated!