How does the free Viking advantage to other Mobile Vikings work?

Only Data
With a Mobile Vikings subscription, you can call other Vikings for free one hour, every day. You also have unlimited free texts to all networks. Do you have an Unlimited subscription? In that case, you can call all networks, including other Vikings, as much as you want. 
For every top-up of your prepaid SIM card you get unlimited text messages to all networks, and an unlimited calling bundle to other Vikings. These expire after a month.
If you choose the Only Data price plan, you have no calling credit or text messages. Other Vikings can call or text you for free, though. Of course, you can call using your data bundle with WhatsApp, Messenger, ...