Indirect questions
Indirect questions are subordinate clauses, so the conjugated verb goes last. Keep a W-question word such as wo or wann. For a yes/no question, use ob (whether/if), not wenn.
Understand the idea
An indirect question embeds a question inside another sentence. It may report what someone asked or politely request information. The embedded part follows subordinate-clause order even if the whole sentence ends with a question mark.
Build it step by step
Keep a W-word when the original question has one. For an original yes/no question, introduce the embedded question with ob. Place its finite verb at the end. The surrounding main clause keeps its own statement or question order. Decide punctuation from the complete sentence, not from the embedded clause alone.
See it in a sentence
Weißt du, ob er heute kommt?
Kannst du mir sagen, wo der Bahnhof ist?
A useful memory aid
Transform a direct question into an indirect one in two steps: choose its introductory word, then move the embedded finite verb to the end.
A common trap
Do not preserve direct-question inversion inside the embedded clause. Also distinguish ob, meaning whether, from conditional wenn.