I don't understand uses of DO, or DOES

* Uses of Do and Does: Do and does are used when we want to ask yes/no questions. We use do or does depending on the subject. Below are two sentences with two different subjects, she and you. for example: >Does she like sport? Yes, she does. >Do you like sport? Yes, I do. *Do: We use do when the subject is I, you, we or they. examples: >Do I know you? >Do you come from England? >Do we have to cut the grass? >Do they want to come with us? *Does: We use does with third person singular pronouns i.e when the subject is he, she or it. examples: >Does he work with you? >Does she have a car? >Does it snow in winter? *Past Tense: Did is the past form of both do and does. for example: >Did he call you? >Did you enjoy it? *Negatives: The negative form of do is do not. In spoken English it is common to use the contracted form of do not which is don't. for example: >I do not like sport. >I don't like sport. The negative form of does is does not. Also, in spoken English we usually use the contracted form of does not which is doesn't. example: He does not like sport. He does't like sport. The negative form of did is did not or when speaking, didn't. example: >I did not know you were coming. >I didn't know you were coming.

I don't understand uses of do or does