drop down menu selection populates column values

I have a workbook designed for department scheduling. On sheet "Shifts" I have a list of all available shifts. Time slots are every 1/2 hour (0000-2330) listed in column A and the name of the shift (S1-S25) going across in row 1. A number 1 is placed in each 1/2 hour interval, going down, to indicate time in the shift. So say for a 4 hour shift I would have 8 1's so they can be totaled at the bottom. There is also a sheet for each day of the week. The sheets are set up like the "shifts". Instead of shift names the employee name is listed in the row. I want the cell below their name to have a drop down box that shows the available shifts (S1-S25) and then when the shift is chosen by the manager I want it to autopopulate the corresponding 1's from the "Shift" sheet to the time intervals on the weekday sheet. I don't know if I'm overthinking this or if I need a more complicated macro. I would really appreciate some ideas!