When you open the poster templates, you will see a standard layout configuration. The default layouts are the most commonly used. It is relatively easy to change or edit the designs. Two methods are shown below.
To change the column layout of your poster using the build-in layouts, Right-Click on an empty part of a column and choose a layout from the available options.
To manually change the column layout, you need to do it on the Slide Master. Click on the View Tab, click on Slide Master, click on the topmost master and edit the columns as needed. When finished, close the master view.