Most of them are in iso files format, Its not just a video tutorials, those are mostly. Labs, it means you open an html file inside that, and you will see 2 parts, one in flash and another in text. At each lesson you finished, you will get to challange flash where you have to practice things you have learned, its like working on real cisco device. You’ll have the flash SSH shell, and you have to type in the cisco commands, and in case you make a mistake, you’ll get wrong alerts and you can then either correct it or need to read and listen to the section again and see the correct answer by clicking the DEMO option, that will show you the entire solution. By the way, this is original cisco materials that you need to pay $$$$$$ for it, but for keen learners it is for freeee!!