Domain mapping NEW multisite BASE domain

I've just installed my first multisite from a Bitnami cloud stack. It is now under -> I want it to be since it is the main blog where I will have all sales etc (and then the subdomains would be, etc)...

My present (non cloud) site for is running still on Hostgator, but I want to transfer to the Bitnami instance.

I read on this site
* to change the domain for your main blog. These options are automatically changed using the following command line tool:
sudo /opt/bitnami/apps/wordpress/updateip --machine_hostname

I'm not sure should I execute that command BEFORE / AFTER / AT ALL I change DNS records to the IP (dedicated in order to map the site to the wanted dedicated domain name: