Hello Genevieve,
I agree with John's recommendations. In addition to that I highly recommend that you thoroughly review "ANNEX A1 THE STANDARD FOR PROJECT MANAGEMENT OF A PROJECT" in the PMBOK Guide, it will help you understand the big picture and how the processes and process groups relate and interact.
Training for Project Management Professional (PMP)®, PMI Agile Certified Practitioner (PMI-ACP)®, and Certified Associate in Project Management (CAPM)®