Add or remove a row or column
You can divide a grid layout panel into rows and columns to organize child objects into a better layout. After you add rows or columns to a grid layout panel, new properties under Layout in the Properties panel are added to child objects to specify which row and column they are positioned in. Additionally, existing Layout properties of the child objects switch to apply to their position in the grid cell (or cells) in which they are contained.
In the Toolbox, click the Selection tool.
Double-click the grid panel to which you want to add a row or column. A yellow highlight appears around the grid panel, to indicate that it is now the active element.
Notice that rulers appear along the top and left sides of the grid panel. When you move your pointer over one of these rulers, the pointer changes to an arrow with a plus (+) sign , and an orange line shows where a column or row will be added. Click anywhere on the top ruler to add a column to the grid at that position, or click anywhere on the left ruler to add a row.
You can either draw your elements on the artboard first and then add rows or columns, or you can add rows or columns first and then draw your elements on the artboard.