Great question! I think the best place to start would be at BiggerPockets.com. They have a BUNCH of free information on investing in commercial real estate that will get you started in the right direction. Before you go hunting for books on buying commercial real estate, browse their site.
If you want to start looking to see what commercial real estate is out there and what prices look like, a site like LoopNet would be a good place to look. It can also be a great place to get hard numbers so that you can practice analyzing deals so when you’re ready to start looking seriously, you’ll have had some practice.
One final suggestion is to reach out to a few commercial brokers and just let them know that you’re new but you’re interested in commercial real estate investing. They might be able to talk you through some basic information and might have some information to give you.
Hope that helps!