Well, there are several ways to effect what you’re after, and while the plugin you’ve installed is one of them, it’s not maybe the easiest.
First: you can put your installation online, and in Options remove all the info about pinging etc. so that technorati et al don’t pick it up right away. If you don’t give out the web address you shouldn’t have visitors.
Second: you can install the blog into a temporary location until you’re ready to go live – like a “putzing” folder – and make sure you “disconnect” the pings to services.
Third: you can install XAMPP from https://www.apachefriends.org/en/xampp.html so you can have a “local” web server, install wp on your home machine as well, and do all the work locally before you upload it live.