Hi Vikram,
We have two courses: On Demand and Premium Live. Both include 6 CATS, 13 required GMAT sessions (3 hours each), and more than 3,400 practice problems of all types, all targeting specific components on the GMAT. The Premium Live course offers an additional 24 hours of live, interactive classes each week that dive deeper into concepts and strategies students are struggling with. The schedule changes month to month based on what students need more help with at the time. The On Demand course offers 6 months of course access, and Live Premium offers a full year.
It's great that you've enjoyed the YouTube videos, though to be honest - they're not very reflective of our current classes. They're pretty dated, and the videos in our course are of much better quality.
As far as instructor help goes, you can post any sort of question on our community forum and receive a reply from another student or teacher. If you're a Live Premium student, you can ask questions via live chat during class.
Hope this answers all of your questions. If you have any more, feel free to reach out!
All the best,
Jessie
Knewton GMAT Team