総務 = the general committee (member)
学級 = class representative
成人 = parents and guardians representative (adult participation representative?)
保健 = health representative
指命 = person in charge of recruiting next year's PTA members
「たくさんの委員がある」= there are many different PTA roles
「その役を選んで」= you can choose which role you'd like
Which role would you like? = あなたはどれをやりたいですか?