"I am here, do you see me?"
Translation:Tôi ở đây, bạn có thấy tôi không?
Okay... So Có and Không do not literally mean Yes or No in this case, but in here, think of "Có" to imply a possibility, Có in here literally means Can, as in Can you see me?
Then think of Không as in like an indication of a question, like it allows you to answer yes or no. Without it, it would be: Bạn có thấy tôi? which could have been a statement if you didn't have the correct tone.
In the exam above, you can exclude Có and the sentence still has the same meaning to the native speaker. i.e: Bạn thấy tôi không?
Other examples: Bạn có khoẻ không? (How are you?) Bạn có nhớ tôi không? (Do you miss me?) Bạn có muốn cưới tôi không? (Do you want to marry me?)
Hope it helps somehow...