Creeperkat -
I would purposefully go back a little bit further than the beginning of the year so you have some sales from the previous year, and then delete the 2022 sales.
To delete them - right click the FULL SCREEN button near the top right, this will display the row numbering. Right click the row number of a row and select "Delete" or for deleting multiple rows, highlight to select multiple entire rows and right click one of the row numbers in that range, and select "Delete"