Using drop down lists

I'm trying to create a report utilizing a drop down list in Excel. I have
successfully created the drop down list, (I'm using every Monday in January
as my different items on my list) but now I want to enter different data
using the same rows and columns for each specific date. This is just a
worksheet that will be used on a weekly basis, I will only need to keep
current week data, but I want to save the previous weeks' information just
for reference. If anyone can guide me to what this is categorized under on
the help page, I think I could figure it out. I'm sure my longwinded
question would be too long to type.

THANKS FOR THE HELP!