Click on the pillar you want to edit and go the Properties panel on the left.

In the left panel, under the Material menu, click on the Select Material drop down menu and click on one of the user-defined materials therein, or click on the Fetch From Store icon at the right of the Material menu to open the carousel and select a material from there.

Go to the Pillar Skirting menu in the Pillar properties tab and click on the righthand toggle button to enable its visibility/invisibility. A default skirting will appear along the pillar's base. To edit skirting, click on the drop-down arrow in the Pillar Skirting menu.

In order to change skirting's dimensions, go to the Dimensions (in mm) menu, and enter the desired values into the T field (for skirting thickness) and H field (skirting height).

To change the material of the skirting, click on the drop-down menu to select a user-defined material, or select to Fetch from Store to open a carousel of various other materials. Select the desired material by clicking on it.