The best way to start with the Selenium at home is to just to take up a good online Selenium training Course and start learning. Selenium is a set of libraries(set of API's) that you can use in your program to automate web browsers. Selenium supports programming languages like Python, Ruby, Java, and C# that means you can use any one of these programming languages to make proper use of functionality provided by selenium to automate web browser.
Now, the question comes back to, how we can master selenium at home, my best advice would be
The first step you should follow is to learn any one of the languages that selenium supports, that will make a good foundation towards learning selenium, and in the long term building your own selenium automated framework in the language you like.
After you are comfortable with any language, the next step is to familiarize with API's provided by selenium.
Now you must have got some idea about selenium API, start using those in your programs, like writing a small script to open any website(say www.intellipaat.com) in firefox. You can do so many things with selenium, keep exploring it.
Once you have some idea about selenium driver, the next step is to learn how to identify elements on the web browser and how to assert them.
Here is a video tutorial which you can also follow to learn Selenium. .
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