Cd mailer box

It looks like you're trying to navigate to a directory called "mailer box"!

To change directories, you can use the cd command followed by the name of the directory you want to navigate to. For example:

cd mailer box

However, if you're using a Unix-based system like Linux or macOS, you'll need to use quotes around the directory name if it contains spaces:

cd "mailer box"

If you're using Windows, you can use the cd command followed by the directory name with quotes:

cd "mailer box"

Once you've navigated to the "mailer box" directory, you can use the ls command to list the files and subdirectories within it:

ls

This will show you a list of files and subdirectories in the "mailer box" directory.