You can print the form at this website, National Poomsae Competition Registration Form. Print out only Form G and sign it. (Form G is at the bottom of the page, you have to scroll all the way down)
For more information regarding the competition, please check out this page, Information.
General Information
Date: 25th and 26th June (Saturday and Sunday)
Time: 9.30am to 9.00pm
Venue: Yio Chu Kang Sports Hall
Regards
Ee Feng