All of our courses are designed to take you for a complete beginner and 0 knowledge to having created an application or website of your own. We take you through the software and tools you have to install, and go through each line of code that you write, piece by piece.
Our videos are only accessible through the One Month app, so you do have to have a reliable internet connection to watch the videos and complete the course.
The Payment Processing course requires you to have an already-created Rails app to add payment processing to. Other apps will work as well, but will require you to find workarounds for some things. However, it does not assume any prior knowledge of payment processing.
For computer hardware system requirements, please see this article.