Making semantic changes

I have been trying to make a semantic change to the default form workspace, but none of the changes I make seem to do anything. I don't seem to have any issue making changes to the HTML templates. If I check here: Adobe Experience Manager Help | Introduction to Customizing AEM form workspace it says I should use the Dev Package, and I see that there is a command to install it, but it doesn't say ​where​ to run that command.

Where can I run this command to get the Dev Profile installed?