Log in to MyAccount at accounts.globe.com.ph
From the Account List page, select your Postpaid account and then click on the "Manage Account" button.
That takes you to your Account Dashboard. Scroll down to the "Boosters" section of the page. The "My Boosters" tab will show you the boosters you are currently subscribed to.
To sign up to an available booster, click on the "Subscribe to Boosters" tab. It will display a list of booster options. Simply pick one, then click "Subscribe".
Click "Yes" to confirm your request, and that's it!