Learn Russian: Завод на западе. - The factory is in the west.

Russian doesn't use a "to be" verb like "is" or "are" in the present tense. To say "The factory is in the west," you simply put the subject and location together: Завод на западе (literally "Factory on west").

Why do we use на instead of в for "in"?

In Russian, you must use на (which usually translates to "on") with all compass directions. So, to say "in the west," you always say на западе, never в западе.

Why does the word for west (запад) end with an "е" here?

Because it is telling us exactly where something is located. After the preposition на, this requires a special grammatical form called the prepositional case. For most masculine nouns like запад, you build this form simply by adding an е to the end, making it западе.

Does Завод mean "the factory" or "a factory"?

It can mean either! Russian doesn't have words for "a" or "the" (articles). You just have to figure out whether it means "the factory" or "a factory" based on the context of the conversation.