VBA to append data with additional information based on row and column reference

I have a spreadsheet with schedule activities that have been exported from a database. I need to append revised dates for each activity based on the Activity ID (leftmost column). I need to have a running history of the movements of the date projections from week to week.
Sheet 1 contains the activities with the current dates. Sheet 2 contains the activities showing dates for each week as additional columns.
I have a very basic knowledge of VBA and I need some help on creating a Macro to copy the current data and append the historical data keeping the previous week(s) dates in the previous columns.
This needs to be done by referencing the Activity ID as I cannont ensure that my export will fill the exact same cells each week.

I have attache a basic file showing what I am tying to achieve.
Any help is appreciated.

Thanks,
Dan