i had my dad to go to get the application form for me during K3 (the time they started to give out the form). just follow the instructions, prepare all documents (reports card, birth cert., baptism cert. {for catholic school}, HKID copy {parent and child}, photo)and send to the primary school that you wish to apply before closing date. i got the "seat" in first round but did not come back. the child must be hk citizen. you can call the school to check what documents they need. the school would prefer the child know how to read, write and understand chinese/cantonese.