I can't explain why you're having difficulty with creating a new selector. It's exactly as shown in the videos. However, the colour picker has changed since the videos were recorded. Just select a colour, and then click away from the colour panel to close it.
Thanks for the reply. Could it just be a problem with the software? I downloaded a trial version then subscribed to Dreamweaver Cloud. The CSS designer does not let me save any changes to the "main css" tutorial file. Even using the new color picker if I click outside the box it still reverted to the original. I created a new test .css.file to see if it was just that the file was locked ( ?) but I still couldn't add new selectors. Does the trial version of Dreamweaver CSS ever have a limited function in CSS designer? I am fairly limited in my knowledge of coding css so I'm stuck using the css designer....
The trial version of Dreamweaver is fully functional. The only limitation is that it stops working after 30 days. If you're having problems with getting the software to work correctly, it might be a good idea to try posting a question in the Downloading, Installing, Setting Up forum, mentioning the fact that you've already posted here (otherwise, they might just transfer you back to this or one of the other Dreamweaver forums).
If you can't make changes to files, it might have something to do with permissions or the user account that you've logged onto the computer with.
When asking for help in the other forum, mention your operating system, and which version you're using. The problem might be related to your computer setup.