There are 5 files when you unzip WonderCMS and one of them is a file called .htaccess(notice the dot in the name).

On some systems, files that start their name with a dot are hidden and can't be copied. To make WonderCMS work, you have two options. Either (1) enable the visibility of hidden files on your computer OR (2) manually create a .htaccess file on your server.

Enable the visibility of hidden files

Once you enable the visibility of hidden files you will see the .htaccess file, upload it to your hosting provider along with the other files where you want WonderCMS installed.

Manually create a .htaccess file on your server (or edit an existing one) with the content below

Options -Indexes
ServerSignature Off
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)$ index.php?page=$1 [QSA,L]
RewriteRule database.js - [F]
RewriteRule cache.json - [F]

After applying either of these fixes, all URLs should be working properly.