Online training can be found through various sources. If you are stuck on how to do one particular task, check YouTube. You can also find GIS and cartography courses. Here are some examples:
A free, multi-day event held annually the first full week of May for faculty, staff and students. Each session is about 11/2 hour long and is usually repeated during the event.
If you really want to learn more about GIS, consider UM-Dearborn's Geographic Information Systems (GIS) Certificate. See the Geographic Information Systems (GIS) Certificate website for more information.