Presumably, they submitted a gTLD application to ICANN and paid the — at the time — USD$180k evaluation fee. They likely also made arrangements with some existing registrar to host the actual name servers, rather than doing so themselves.

They may or may not have then had the evaluation fee refunded to them, under the Applicant Support Program (https://newgtldprogram.icann.org/en/application-rounds/round...).