@Conny64 

Hi,

- click on the tab "Erweitert" (to the right of "Basiseinstellungen")

- click the menu "Netz" and then "Internet"

- scroll all the way down and click on "Profil erstellen"

- enter a new unique "Profil-Name", select "APN Typ:" "Statisch" and in the field for "APN" enter the new APN you want to use

- for the remaining settings just use the same values as in the profile shown in your screenshot

P.S. If there does not exist an actual user name and password for the APN you want to use, then you can usually just enter anything you'd like in those two entry fields.