Hi anatwick,
you do not need to put anything in the yourFolderHere portion; this was just meant as an example if you have any custom directories below the /opt/mattermost parent directory, because if you do, the documentation will remove all of them by default. If you do not have any custom directories (which you most likely don’t, otherwise you would know that), you can skip this command. It was meant as an alternative to command above in the documentation.