Rabbi Avraham Spector, z"tl, wrote "Sefer HaGabai", a comprehensive guide for the Gabbai.
There are Hebrew and English editions of the work. The Machon L'Rabanei Yishivum of Kiryat Arba published it ten years ago. If someone wishes I will be happy to send them a copy of the sefer in Hebrew or English for eighteen dollars.