There is no secret that Magento is the most popular eCommerce CMS in the world. But when you decide to work with Magento (taking into account that you are already familiar with PHP, Javasript, MySQL) and download its archive, you could be frustrated when you see all these hundreds of folders and thousands of files.
A few years ago there was a very limited amount of information provided by Magento itself. In my opinion, this fact and complexity of the platform lead to the situation that even if you want to do everything right, it’s hard to say which way is the right one. But time has changed and there are a lot of good sources developed by Magento and its eco-system.