Selenium is the library for which you need a programming language. You can use popular programming languages like C#, Java, Python, etc. Learn the OOPs concepts using any of the above-mentioned languages. Selenium library contains classes, methods, properties and enums. If you like reading the stuff then you can read the following Selenium Tutorial. You can use the following video tutorial to learn Selenium. .
Before getting into the testing do follow the below-mentioned steps:-
Step 1 - Install Java on your computer
Step 2 - Install Eclipse IDE
Step 3 - Download the Selenium Java Client Driver
Step 4 - Configure Eclipse IDE with WebDriver
This is the high-level way to explain how to install Selenium and now about testing.
here is a sample piece of code which might help you understand how selenium script works.