You’ll find all the materials needed to study for your CCNA exam here.

On the left side (or below on mobile) you’ll find a list of articles covering all the exam topics, organised into chapters. The first couple of chapters describe some basic networking terms and devices, the later chapters go a little bit more in depth. You can start reading the articles from the beginning to work your way through the exam topics in a logical manner, or you can find a specific article that interests you.