Technically, most of the answers to your question depend on what you are doing - but for efficiency, it's better to limit transfering from client to server (or vice versa) as much as possible.
Really, I suggest going through some tutorials, look up "modern OpenGL tutorials" or similar. Make sure the tutorials are "modern" or at least version 3 or later. For example, this one http://www.opengl-tutorial.org/ seems good, I believe it was one of the tutorials I skimmed through it when moving from XNA to OpenGL a year or two ago and found it helpful.
After you get the basics, going through the OpengGL wiki is helpful on the nuts & bolts aspects of OpenGL.