I'm trying to ask a question about the future. So which form of the verb "will" should I use?
So, when will it be there?
So, when would it be there?
Just talking specifically here for their usage in the future tense:
Both are used for the future. The difference is:
Would is used when the thing discussed is only planned, and not for sure.(subjunctive)
Will is used when the thing is already planned, and confirmed that it is going to happen.
Would is used to:
Would is also the past of will.
Will in your example is used for a fact: Something will be there, and you want to know then.