Do & Does

Do and Does are auxiliary verbs used in the simple present. 
QUESTIONS
Questions with verbs in the simple present use the auxiliary verb “DO”.
Structure 
Do/Does   +   Subject   +   Base Verb
Examples:

• Do you like pizza?
  
• Does she play baseball?
  

Answers 
The answers to do/does questions are always "yes" or "no".
This is why they are Yes/No Questions. Question:        Do you like chocolate?
Answer:           Yes I do.
                  No I do not.

Question:        Does she have a brother?
Answer:           Yes she does.
                  No she does not. 
NEGATIVES
Negative sentences in simple present use do or does.
Structure 
Subject        +        Do/Does        +        Not        +        Verb
Examples:

• I do not like hockey
  
• She does not live in Brazil.
  

Contractions 
Do not  =  Don't     
Does not  =  Doesn't

Examples:

• They don't have a dog.
  
• He doesn't want a drink.
  

VERB STRUCTURE The verbs after "do" and "does" are always in the base form.

Examples:

• She plays hockey.
  
• She does not play hockey.
  

The subject of the sentence only changes the "do" or the
"does".  The verb is always a base verb.

• Does she live in New York?
  
• Do they live in New York?
  

• He does not have a brother.
  
• They do not have a brother.