Grammatically, 'would' is a past tense. the problem is that we don't use it only to refer to past time, and, indeed, we mostly use it to present or future time.
I would love a coffee. - Present time. 'Would' here is used to be polite or to express a wish.
I would come tomorrow if I had the time. - Future time. 'Would' here refers to the future, but it is an imaginary future because I won't come as I don't have the time. It is being used to make an excuse. It can also be used to talk about events in the future that are very unlikely to happen.
Whenever I went there, I would buy some CDs. - 'Would' here refers to the past, and is used for a past habit or repeated action.
I would have helped if I'd known about the problem. - 'Would' here again refers to the past, but it refers to an imaginary past- the opposite of what actually happened, so we use have + past participle after it to show that instead of an infinitve without 'to'.
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