I'm struggling to get a formula to populate a list

Hi,

I am trying to put together a new staff rota on Excel and I am having a nightmare. I am looking to create a rota which takes names from my available list and then populates my 'duty spreadsheet'. I have 4 members of staff handling telephone enquiries - 2 in the morning and 2 in the afternoon. I also have 2 members of staff on reception duty per day. Each (available) member of staff must do 1 day on reception and a half day of telephony work per week. I'm having a nightmare trying to figure out how to get this spreadsheet to populate automatically. Can it be done? I just cant get to grips with formulas!! Help!

Please find my attempts thus far attached.