Say you have an Excel sheet with the range A2:D10 selected, as shown below.
To deselect cells from Column B (range B2:B10), press and hold CTRL on the keyboard, and drag through the cells you want to deselect.
As a result, the cells in Column B are deselected, while ranges A2:A10 and C2:D10 are still selected.
Deselecting cells in Google Sheets works in exactly the same way.
