you have walked through all the steps now, it seems. Not sure what else the problem can be. There now doesn’t seem to be a remote, so now adding a remote should go fine.
@renbozhang can you please check the output of the pwd command in the terminal? I am expecting that you’ll get this:
$ pwd
/home/ccuser/workspace/daw
The reason that you’re unable to complete the git remote add origin command is because the daw directory is not a Git repository.
Exercise #3 (Initialize Your Repo) has you change into the personal-website directory and initialize a repo there (with git init), however this does not appear to persist when you move to Exercise #4 (Add the Remote).
If you cd into the personal-website directory, and then try and add the remote, everything should work (presuming that you correctly initialized it as a repo in the previous exercise).
(I’m also going to move this to the Bug Reporting category, and will log it with CC.)
doing cd without any arguments will take your to your home directory. Which means you are not in the right directory to complete the exercise. You should be in your personal-website directory as pointed out by @thepitycoder