If you are looking to learn a new skill or want to find out how something is made or put together then you start by searching the internet for tutorials. There are millions of tutorials on the web for many different subjects from building a flat packed wardrobe to programming a website and most of these are free.
Depending on what you need the tutorial for, YouTube is a great place to start. Often manufactures of products put videos online to show you how something works or is assembled and many professionals also upload their own videos showing you a step by step guide to learn something new.
Often watching a video helps you to learn a lot quicker than reading instructions or studying books as you can physically see what you need to do. If we look at programming, for example, it may be that you are unsure of where to find a certain bit of code within hundreds of files that requires editing. Watching a simple tutorial may be able to take you straight to it saving you hours of searching.