I put a wrong domain-link in the setting – how can I rescue my blog?

Unfortunately, I changed my domain settings with a wrong forward-link, safed it… and now, my blog is gone – page not found…
I can’t access the dashoboard anymore (login/ page not found) and I don’t know how to enter again and change the error! Can anybody help me??? that would be sooooo good! thank you in advance
Blog url: https://www.silvias.net/

PS: I still have access to my server, and can download and open the wp-files – but I don’t know which file I should modify & how to modify it … (of yourse, I’m not a specialist, but a simple user…)