There are several ways to find reports for the work hour log (WHL) module:

1) Type RPM in the program field and press ENTER. The reports are sorted by modules. 
My favourite reports lists reports that you have added to your your personal report list.

Click on the preferred module name, in this case HumanResources, and you will get an overview of the reports sorted by sub modules. The numbers to the right show the quantity of reports linked to the specific modules/sub modules. You may click on the numbers to display all the reports connected to this module.

2) Type REP/*WHL in the program field and press ENTER.

This lists reports where 'WHL' is part of the name or description a report.

3) From the work log approval (WLA) application, you will find 'Reports' in the context menu selection: