original:
Download Cars (one-by-one) @ ASR Formula 1991 - Developer Ressource

Download Track @ https://www.racedepartment.com/downloads/fonteny.30137/download

The <INSTALLATION_FOLDER> usually is located in:
C:\Program(x86)\Steam\steamapps\assettocorsa\

You can find your Track-Directory in:
<INSTALLATION_FOLDER>\content\tracks\ <---

The track directory of the new track should reside here.

th3d0c's Discord
th3d0c's Website