Geia sou Eli kai kalwsirthes sto forum.
Tha sunexisw sta agglika (gia na katalavainoun kai oi upoloipoi ti grafoume...)
You can export each drawing from ArchiCAD to AutoCAD by opening the floor plan/section/view you want to export and from the menu File->save as-> and choose DWG as the file type you want to export.
In this dialogue there is a settings button from which a window with the available translators will open. You can duplicate one of the existing and adjust its parameters (units, Acad version, layers and other translation parameters).
If you want to export 3d information you have to export as DWG from the 3d window.
This is the simplest method, there is a more advanced method (publishing) but needs more experience.
You can find more information in the documentation of ArchiCAD and also by using the search button(top of the page) in this forum.
As for your second question I believe that if you choose to use Archicad as an interior designer Cigraph's ArchiForma addon is quite useful for furniture creating etc.
Petros
ArchiCAD 22 4023 UKI FULL,
Archicad 21 6013 UKI FULL, ArchiCAD 20 8005 UKI FULL
iMac Retina 5K, 27-inch, 2017
4.2 GHz Intel Core i7
32 GB 2400 MHz DDR4
Radeon Pro 580 8192 MB