Answer: Mao Zedong’s speech intended to explore three main ideas which were the concept of death, any action that was taken in the revolution is valid and every people had to support the revolution. And the figurative language that he used, was to explore some metaphors such as Battalions which are the Communist Party, Eighth Route, and New Fourth Armies. He also used the words feathers or Mount Tain to talk about the death of some people.
You are already a prose writer if you have written poems, or human conversations are examples of prose. Essays are also examples of prose writings and I am sure you have written some of those!
I guess formal and informal refer to two types of essay - you can write a formal essay where you avoid conversational language and such and where you need to be very professional, or you can write informally where you don't have to think about such things, it is very casual.
