What did you change then exactly? Did you just edit the example.html / index.html page or did you change a lot of other things in other files?
If you compare the new files with the old ones you can see what’s changed and see if anything is different. If you have customized the main.css just compare that file. If you costomized the index.html then check the index.php file and see the differences. Basically you should be able to copy any customizations into the new files from your old ones without much trouble if you do it properly.