you post that you see in the selection "display 1" and "but i cant add anything more"
that sounds for me you are willing to tell this forum that you have not only this One display (more then 1 Display)
Currently we are stupid , we don't know the setup you have, you not postet a logfile that contains this required information
Related to that what you posted "Display 1" it tells me that you have more then One display? The default Name of Single Display Setups is "Display 0" the counter for display name tags start with 0
if this speculation true that you have for example 2 or 3 Displays
then Only this one is shown by the reason this is the only of this 2 or 3 or 4 displays connected to the same "Brain" that Generates the Image
if there multiple other Displays that not seen in this list, there are (the cable) not connected to the same area of your PC
Tower/laptop we don't know we have no log that show us your hardware, so we need to speculate again
without a log and a specific error report and question we speculate here the next 2 days
if you are a "computer" "baby" its fine but then write this in the first that you have 0 or near 0 know about all that if you ask a technic question