Time clauses are used to indicate a period of time based on an action. Time clauses are introduced by conjunctions before, after, till, until, as soon as, while, when, whenever and expressions such as the moment, the minute.
Future tense cannot be used in time clauses to describe future events. In such cases we use the Present Simple.
I will come on Monday after I finish my work.
He will help his mother when he comes home.
We use the Present Perfect in time clauses to emphasise that one activity will be completed before the other starts.
I’ll call you as soon as I’ve arrived.
They will buy this house after they have saved up money.