Hi Guillerm,

Looks like you installed another AutoCAD for Mac version - not 2018. So you need to uninsrall it at first with Remove AutoCAD application, which you can find in Autodesk ->AutoCAD (your version number) folder.
Then you need to use full installer from here:

https://knowledge.autodesk.com/support/autocad-for-mac/downloads/caas/downloads/content/autocad-for-...

And install AutoCAD again.