How to get your contacts here
Export your contacts as a .vcf or .csv file, then choose it with Import contacts file. Most phones can do this from the Contacts app. On Android, open Contacts, then Settings, then Export. On iPhone, open icloud.com/contacts, select all, and choose Export vCard. Google Contacts at contacts.google.com also exports vCard and CSV.
The file is read in this page and the contacts are saved to your account or this device. Numbers without a country code get the one from your last scheduled message (default 91).