To change them:
1. Highlight the required unit/s that need to be a different colour and right click.
2. Select 'Edit Materials' - Here you can edit the materials as you usually would by selecting the components and selecting the texture.
3. You will then need to create the corresponding attachments of the units you have changed (cornice, plinth, pelmet etc.) as the colour of these will also need to be altered.
To individually change attachment materials such as cornice, pelmets, plinths etc.
1. Highlight the units that require the attachment with a different material and right click.
2. From the menu select 'Customisable Panels'.
3. Choose the required attachment from the list - this will create a new attachment.
4. Right click the new attachment and click 'Edit Materials' - Here you can change the material as you usually would.