Changing the settings to modify layout of Media Wiki for website

Hello!
Could I change the settings to modify the layout of Media Wiki for my website? There’s a continuous error prompt message shown, whenever I try opening the Wiki webpage in my computer. I tried to access by encoding https://www.techyv.com/directorypath.
However, when I try to put http://www.systemname/directorypath there is an automatic error shown. It doesn't run after that. The error displays “Page not found”! Why is it so?
Please help.
Thank you.
