Project tips
The documentation for the obj loader is here. This is my loader. If you find bugs, let me know! You should use the loader from a recent project (ShadowMaps should be good), because I recently fixed a bunch of bugs.
You can also use other loader if you prefer; assimp is a good one.
You might want to turn on compiler optimizations when running your code. You shouldn't debug with optimizations, but it will make your CPU code run much faster. For command line compiles, replace -O0 with -O3. For Visual Studio, turn on 'Release' mode in the toolbar. I don't know how to do this in XCode.
You can load and render multiple models. You can load each model into a separate buffer or you can load all models into the same buffer, but keep track of their bounds. Then, when rendering, issue a separate draw call for each model using the appropriate bounds or buffers.