Why we used do and be verbs in these sentenses
This question relates to action verbs and linking verbs, and my comments relate specifically to the simple tense forms of verbs. An action verb denotes an action, such as an overtly physical action like 'walk' or a more subtle action like 'watch'.
Action verbs are often followed by objects (watch TV) or prepositions (walk to the school).
"do" is a nonspecific action verb meaning to 'perform/execute/carry out' some task. Let's do something.
"do" is also an auxillary verb and is often used for emphasis. Rarely do we see so many bears. I do like you.
are you fine? "be" is not an action verb, but a linking verb. Linking verbs connect the subject of the verb to additional information about the subject, and are followed by an adjective or a noun. We are fine. He is my brother.
why we do not use do??? Because their is no action. You aren't doing anything; you (just) are fine.
do you play a game? This sentence is a bit odd.
You can ask, 'Do you play any games?' or 'What games do you play?'
why we used do not are?/ Because you cannot substitute the linking verb "are" into the above two present tense sentences.
You can say 'Are you playing any games?' and 'What games are you playing?', but now we are into continuous tense and off the topic of your questions.