[statement] + 吗?
吗 turns a statement into a yes/no question. Put it at the end and change nothing else.
The word order of the statement survives intact. English inverts the subject and the verb to ask a question; Chinese does not move anything.
There is no word for "yes". Repeat the verb to agree, and negate it to disagree.
With 是, the answer is 是 or 不是. With 有, it is 有 or 没有.
A sentence that already contains 谁, 什么, 哪儿 or 怎么 is a question, and adding 吗 breaks it. nǐ你qù去nǎ r5哪儿má吗 is wrong. Say 你去哪儿?
吗 is ma with no tone. It carries no meaning of its own and adds no politeness – the question is neutral either way.