Sorry for the inconvenience. Known Navigation header breakage, its being "rebuilt" but forward nav should be ok now.
There may be other unforeseen breakage primarily in the handbook portion of the wiki.
The Table Of Contents section of each "PC-BSD® Users Handbook" page may be the best workaround.
Maske zur abgeschlossenen Nachinstallation
The screen in Figure 4.7a indicates that the post-installation setup is complete.
Click the "Finish" button to access the login menu.