If you want to summarize data by day for events between 6pm and 9pm, this should get you started:
YOUR_BASIC_QUERY_HERE (date_hour>=18 AND date_hour<21) earliest=@w1 latest=@w6 | timechart span=1d count
Given your example, I assume you want results for Monday through Friday. If you wanted the full week, use earliest=@w0 latest=@w6+d.
... View more