You set the properties of columns and column layouts by using the Columns Toolbar.
To fly in the Columns Toolbar:
From the scope menu you can choose to modify the entire columns layout or a particular column.
If you choose to modify the column layout, the action menu will provide options for setting the number of columns, their width and position, and the default spacing between the columns. If the section contains more than one column layout, you can delete a column layout, optionally merging its contents with the previous column layout.
If you choose a specific column, the action menu will provide options for setting the width of the column and the width of the empty space between the column and the next column. You cannot make the columns and column spacing wider than the width specified for the column layout.
When setting the width of a column, it is often convenient to express the column width as a percentage of the overall width. For example, if you change a layout from 2 columns to 1 column, you probably want the width of that one column to be 100%. If you right-click on the text field that shows the column width, you will see that percent has been added to the list of measuring units. If you choose percent and type 100 into the text field, the column will resize to its maximum width.