At this point currently, there is no part 2. However, there are forum posts that deal with what to do after HTML/CSS Part 1. At this moment I cannot refind them but I am sure if you post in the community section about what to do you could get some great suggestions like websites to try etc.
Following those, learn git would prove to be useful if you ever decide to use github. If you do decide to learn git, learning the command line would prove to <span style=¨color: blue¨> be useful.