Click on a time to schedule a meeting. You are free to choose any time, but if there are multiple times that work for you, try to choose one directly adjacent to a period when I am NOT free. This keeps my time less fragmented.
When you arrive for your scheduled meeting time, make sure you knock or poke your head in or otherwise let me know you have arrived, even (especially) if I am in the middle of a meeting with someone else. In general I probably won't remember to come check whether you are waiting.