You select a column by clicking on the column header.
To select multiple columns simultaneously, proceed as follows:
? Adjacent columns:
Select a column, choose Shift or Control, and select the required columns, or
Choose Shift, and select the first and the last of the required columns, or
Select a column, keep the mouse button pressed, and drag the mouse over the desired columns.
? Columns that are not adjacent:
Select a column, choose Control, and select the desired columns.
To deselect individual columns, press and hold the Ctrl button and click the relevant column header.
Selected columns have an orange background.