Once you will search on the web you will find there are many free tutorials and video tutorials that are available free of cost. To learn Selenium, you must learn the concepts properly. So, I would suggest some of the Selenium tutorials, blogs and video tutorials that you can refer to learn Selenium. If you are a beginner in Selenium then this blog will guide you in the best possible way.
Here are the links that I am talking about:
Selenium Tutorial
Selenium Training Course
Once you will go through the blogs you will get some insight into Selenium. Watch the video tutorial on Selenium to learn more concepts of it.