How did a 21-year-old man build his own country with just 400 citizens?

The 21-year-old British-Australian Daniel Jackson founded the self-proclaimed micronation Free Republic of Verdis in 2019 on a 0.5-sq-km plot of land between Croatia and Serbia. Jackson and his friends claimed the territory and declared him president. Verdis says it has around 400 citizens, laws and its own flag. Jackson recently received a humanitarian award presented by IPPDR at UN headquarters.