Does is used only for the third person singular: he/she/it
1.Determiners introduce the noun and define it in relation to the context and the speaker. They are situated before the noun and, consequently, before any adjective defining it. This class includes:
1a) articles: definite the and indefinite a/an.
e.g.: An apple a day keeps the doctor away.
e.g.: The black cat crossed the road.
1b) demonstrative adjectives: physically or emotionally close this/these, distant that/those.
e.g.:I like this chocolate cake (I'm eating now), but I didn't like that apple pie (I ate) yesterday.
e.g.: These ideas are much more interesting than those we had to hear last week.
1c) possessive adjectives: combine with the noun my,your, his, her, its, our, their.
e.g.: my garage, your friend, his car, our house, their family.
2.Adverbs are used to modify adjectives, verbs and other adverbs. Most of them derive from adjectives by the addition of the -ly suffix, But not all of them do so.
e.g.: suddenly, quietly, really, proudly, stupidly, angrily etc.
e.g.: very, now, then, there, quite, later, often, here, rather, outside, instead, perhaps etc
Adverbs relate to what they modify by indicating time (now, usually, often), place (here, there, inside), manner (beautifully, entirely) or degree (very, quite, rather).
e.g.: We must leave right now. It's getting too cold outside. It depends entirely on you. I'm quite tired today.
3. Infinitive and 4. Gerund.
Infinitive is the "to" form of the verb. e.g.: to speak, to work, to see, to help etc
Gerund is a noun made from verb + "-ing" form. e.g.: parking, waiting, cooking, reading etc
Both can be used as the subject, the complement or the object of a sentence.
e.g.: Reading helps you improve your English. (subject)
e.g.: Her favourite sport is swimming. (complement)
e.g.: I like cooking. (object)
e.g.: To learn is important. (subject)
e.g.: The most important thing is to respect others. (complement)
e.g.: He wants to sing. (object)
Both can be made negative by adding not.
e.g.: She enjoys not working.
e.g.: I promised not to tell anyone.
The most used verbs that are followed by the "to" form: agree, choose, decide, expect, forget, hope, learn, manage, need, offer, promise, refuse, seem, want.
e.g.: Tom agreed to help me. I chose not to answer. I decided to wait. He expected her to arrive early. I forgot to lock the door when I left. I hope to begin colledge this year. She learned to speak Dutch when she was a kid. He managed to solve the problem. I need to study. Sam offered to do the dishes. She promised to stop smoking. The guard refused to open the door. Anna seemed to be disappointed. I want to go home.
Infinitive without "to"
It is used after the auxiliary verbs and modal verbs: can, could, may, might, must, will, should, would, do, shall, let's, had better, would rather.
e.g.: I can speak German. Could you speak more slowly? May I smoke here? They might be late. You must leave now. It will rain tomorrow. You should be at home. I would like a cup of tea. Do not stop! Shall I get you some water? Let's have a drink. We had better leave now. I'd rather stay here than go home.
The most used verbs that are followed by the "-ing" form: like, love, adore, enjoy, prefer, hate, can't stand, don't mind, finish, keep, understand.
e.g.: I like cooking. He loves reading the Suday newspapers. I prefer watching a film tonight. She hates cleaning the bathroom. He can't stand her singing. I don't mind waiting for you. He finished doing his homework. I have to keep working. I understand his quitting.
All prepositions are followed by the "-ing" form: after, before, for, at, without, up, on, about etc
e.g.: After seeing the doctor I felt better. Before going to bed I usually read a magazine. Thank you for inviting me. She's good at swimming. Can you get here without changing? I gave up smoking. He has to keep on walking. He's thinking about studying abroad.
Note: verbs like, love, adore, prefer, hate are sometimes used with to but -ing is more usual and more general in meaning.
e.g.: I like cooking. - We refer to the action itself
e.g.: I like to cook beef on Sundays. - We speak about the consequence of an action or a specific instance.
Thanks for the article.
If you are interested in the difference between DO and DOES, you can continue for more details: https://en.learniv.com/info/en/irregular-verbs/do-vs-does-the-difference-between-do-and-does/