Read books. There are some great books on programming out there. I would strongly recommend a A Players Guide to C#. It’s structure, practice problems, and explainations of the basics were far better than any free guide to programming that I’ve seen online. There are a lot of other great books out there too.

It also doesn’t matter too much about a book being outdated when you are only studying the fundamentals.

A lot of the stuff you read online has never been fact checked or edited for clarity. Some of it is great, but most of it is not.