"We turn right at the museum."
Translation:Wij slaan rechtsaf bij het museum.
- slaan = to hit
- afslaan = to turn (in the sense of turn left/turn right)
- draaien = to turn/to spin
Only the second one you mention is correct, the first one is about hitting, not about directions. The third one is not correct because afslaan is a separable verb, so the af part of the verb moves to the end. The fact that af is not a separate word, but linked to rechts is specific to this verb, see more explanation here (in Dutch).