how do I get a temporary international coverage

You do need to talk to an agent at the store or calling. Don't bother with the store on 6th Street close to Arby's they're just a seller of phones they are not a real Verizon store. They are rude and won't even bother to help you unless you're buying a $1,200 phone

If you have a Verizon phone you have to talk to a agent or a employee at a local store.