In-House Report is found inside the Statistics Tab, in the Reports function.
At the top it will show the total number of rooms occupied versus the total number of rooms, occupancy rate, the estimated income for the day, and the paid balance for the day (money received).
Below in list form, you will see all the guests who are currently checked-in for that specific day. Please note that if a guest's status has not been updated to "Checked In" they will not appear on this report, even if they are in reality "In-House."
You can also export a CVS (spreadsheet) version of this report, generate it as a PDF or print a copy by following the blue buttons at the bottom.