If the name is available, you can register it with any of SGNIC’s accredited registrars <link to https://www.sgnic.sg/list-of-registrars.html>. It is on a first-come-first-served basis for all NDN made up of 4 digits or more, in any combination of digits. All 6 extensions of names are available for NDN subject to approval for some of the categories such as com.sg, org.sg, edu.sg etc.
The application is almost real time unless it falls into pragmatic application that requires SGNIC to manually approve. In such a case, the name applied is put on hold until a decision is made. If approved, the name will be assigned to the applicant; if not, the name will be purged for general availability.