Learn first about what is plc, understanding operation,editing programming etc... of plc is one good thing to started. Now that you had a GE PLC ask to your supplier technical support they may had a training program for thier costumer. If this is your first time in plc, study one brand of plc first and learn it properly do not study different type in the same time. Once you learn one brand of plc it may help you to learn others.