I will be doing it.
Indonesian: "Saya akan melakukannya."
Explanation: The continuous aspect is often understood from context.
I'm going to be doing it.
Indonesian: "Saya akan melakukannya."
Explanation: Similar to "I will be doing it."
I'm going to be working all day long tomorrow.
Indonesian: "Saya akan bekerja sepanjang hari besok."
Explanation: "Sepanjang hari" means "all day long."
I'll be starting at 9 and finishing at 4.
Indonesian: "Saya akan mulai jam 9 dan selesai jam 4."
Explanation: "Mulai" means "starting," "selesai" means "finishing."