Output specifc data based on dropdown selection

I have been working on a spreadsheet to track payroll and I seem to have reached the end of my knowledge with Excel. I am paid twice a month, on the 1st and 15th but my pay is offset two periods (essentially one month). I am trying to make a spreadsheet that I can enter my times into everyday that will easily allow me to look back and estimate how much I should be getting on my check when it comes that time. Since I get paid for my previous months work I don't generally remember what hours I worked during the pay period in which I will be getting paid. Thus my reason for needing this spreadsheet.

I have most of the sheet done, but the problem I am running into is with the dropdown box that lets me select the pay period. I would like the sheet to be as small as possible, which is why I added the Pay Period dropdown box. The function I need this to provide is to change the cells in orange depending on the pay period selected. For future periods I would need the times blank, but the dates filled in.

My question is, how would I go about doing this? I know it is possible as my father received a timesheet that did this very thing from his work, but it is locked and password protected so that he cannot edit it. I would just look at the formula in his sheet, but I cannot due to it being protected.

I would much appreciate any assistance that you can provide, or any advise that might point me in the right direction. Attached is my current sheet.