In that package there is an 'Accessory' add-on that allows you to add surfaces to roofs - beware, you will increase the polygon count of your model by a lot potentially - especially when you start adding roof tiles.
You can find other 3rd party objects that work with these accessories.
Some are free, others are not.
Generally I would only add 2D fills to a detail - but you can add them to any section/elevation that you want to.
Generally you will not get the level of detail you need from Archicad elements themselves for large scale details, so you need to start adding further detail by adding lines, fills and 2D objects.
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