its not particularly complex... you just need to understand how the data builds up into your report.
Now then, looking at the report sample, it would appear you want to report "The hours worked on each project by each employee"... I could give you the sql for this, but I think you would be better off (since this isnt complex at all) doing it yourself.
Here is how... open a query and then add the Hours Worked table. Click the "Totals" (sigma sign, spikey E symbol!) button... then simply add Employee, Project and Hours. You then need to set the "Total" option to Group for those you want to group and Sum for those you want to add up, ie: Hours.
Once you have the base query working how you want it to work, simply add in any other tables or fields you would like, but ensure any additional tables and fields are not going to "dis-aggregate" your groups.
This isnt complex in the slightest, assuming you know your data the best way to achieve this, imho, is to play with the group function for a while to get a feel for it.