the 'roles & responsibilities' of helpers are included at the last 2-3 pgs. it's not specifically duties of ah-yees but for helpers in general. most of the time, ah-yees are helpers. the bride or the overall coordinator will need to assign roles for the helpers - cannot all do same thing right?
if it's pure ah-yee and not helping in any aspect of the wedding, then it's simple... turn up early at bride's place, plan how to sabo the groom, sabo the groom, get the ang bao(s), follow bride to groom's place for tea ceremony and back. the ang bao money is to be divided among all the ah yees.