An adverb clause serves the purpose of an adverb.
ADVERB CLAUSES OF TIME
Adverb clauses of time are introduced by subordinating conjunctions like when, whenever, before, after, as, since, till, once and now that.
1.when you heat ice, it melts.
2. After the match ended.
Once and now that are sometimes used as conjunction in adverb clauses of time.
Once you have made a decision, you must stick to it.
ADVERB CLAUSES OF PLACE
Adverb clauses of place are introduced by the conjunction where and wherever.
1. Where there is a will, there is a way.
2.That is the place where I was born.