Numbers - how do I retain data in a cell

Hi everyone.

Any help appreciated. I would like to record data into a spreadsheet daily and refer back to it at a later date. I am using two sheets , Input and Data, see photos. The input screen date changes daily and I enter the data. This is then logged in the data sheet at the matching date. Unfortunately when the input date changes and I enter new data. The previous data stored in the data sheet is lost or replaced with the new value even though its a different date. How do I keep the data from previous dates (inputs) in the data sheet?

I hope this makes sense and thanks for taking the time to reading my post.