|Dont know if you still need help with this, but there is an easy way of adding your hours up etc.|
If you enter your time in the way of hh.mm in each cell, and format that cell in the same way, then add a total collumn to work out the difference, which is basically finish time minus start time. Do that for each day, inc your hour or 30 mins for dinner or whiatever. So your total for that day works out as your working hours.
Then at the end, for total hours worked that week, right click on the cell and go to Format Cell, then select Custom, and put in [h]:mm in the custom box. This will add up all your hours rather than trying to work it out in time.
A1 = 08:00 (start time)
B1 = 01:00 (dinner break)
C1 = 17:00 (finish time)
In cell D1 enter the forumla =SUM(C1-B1-A1) - this will give your total working hours for that day in question
Do the above for each day, then once you have your totals in D1, 2, 3, 4, 5 (for Monday to Friday) enter =SUM(D1+D2+D3+D4+D5) for your total for the week. Make sure you format the total for the week cell in the custom format of [h]:mm (otherwise it will add it as time, and only go up to 24 hour clock then go back to 00:00 and start again)
Hope this helps.