Once your site is live, log into your Google Search Console account.
Make sure you log in with a Google account. Usually these are emails that end in @gmail.com but if your company is using google apps they might end with your company's domain name.
Look to the right of your site and click the “Manage property” dropdown:
Verify your site by adding a meta tag
If the site does not verify immediately, wait a couple hours and try again. There could be a delay on Google's end on the verification.