Do I need to take up courses for SEO or can I just learn more quickly over the internet?

[Susan]

I have been in communication with some SEO companies out there and have had business dealings with them. I just want to expand my knowledge and some of them have been kind enough to provide me with material and help through guidance and practical involvement while dealing with my own and some of my business clients business ventures. But to learn it properly do I have to put aside time for courses or can these companies and other resources on the internet like Google provide me with enough. Please consider the time factor, which would be easier and less time consuming.