How is the national electoral register created?

Chapter 541 Electoral Affairs CommissionOrdinance 02/08/2012

The functions of the Commission are-

…

 (d) without limiting of generality of paragraphs (b) and (c), to-

(i)  supervise the registration ofelectors;

(ii)  regulate the procedure at anelection; and

(iii) conduct or supervise promotionalactivities relating to registration of electors;

…

Section 7 Regulations

(1) The Commission may, by regulation,provide for the following-

(a)  the-

(i)  registration of electors;

(ii)  determination (where applicable)of-

(A)  the appropriate constituency;(Amended 2 of 2003 s. 68)

(B)  in the case of the ElectionCommittee, the appropriate sectors or subsectors; or (Amended 21 of 2001 s. 59;2 of 2003 s. 68)

(C)  for an election held for electing aRural Representative for a Rural Area, the appropriate Rural Area or RuralAreas, (Replaced 5 of 2014 s. 64) for such registration;

(iii)  form, compilation, revision andcorrection, and the manner of publication of the register of persons entitledunder any electoral law to vote at an election; and

(iv)  ascertainment of qualifications ofelectors;

Source: http://www.legislation.gov.hk/blis_pdf.nsf/4f0db701c6c25d4a4825755c00352e35/B1CF624C2B6AA815482575EF0016AA19/$FILE/CAP_541_e_b5.pdf