Select Year To Show Date In Day?

Basically I got to create a spreadsheet which needs to last 10 years......my workbook, has set up tab, a tab for each month, and a summary sheet.

At the start the end user needs to select a year in cell 'Set-Up & Info'!B8 (i use a dropdown box, so they can select the year)

I then want my April tab to think 01/04/ then the year which is in cell 'Set-Up & Info'!B8

I then custom format the cell below to show what the day is (Custom format "DDD"), so it the row below needs to be in a date format.