Can you please help me on how to use "have", "had", and "have" in a sentence.
Welcome to the forum. I have a few pieces of advice which I have put below. The first two will help you with your future posts and the last two refer specifically to this question.
1. Please remember to start every sentence with a capital letter.
2. Please put the words you are querying in quotation marks, or italicise them, so that they stand out from the rest of your sentence.
3. You have repeated "have" in your question.
4. There is no simple answer to your question. "Have" and "had" have several usages and it's not possible to simply say how they are used in one sentence. Please post some sentences using "have" and "had" and we will try to see what you are confused about.
can you please help me on how to use have, had, and have in a sentence.
The verb "to have" and its derivatives can be used as a main verb or as an auxiliary verb.
If it is the only verb in the sentence, "I have a car", it's a main verb - meaning "to possess ..." (You can check a dictionary for its meanings).
If another verb follows it, it's probably an auxiliary, "I have bought a car." (You can see any basic English grammar book or webpage for the use of "have" as an auxiliary.)