To install Omeka S it redirects to a /install directory which doesn’t exist, nor can I find it anywhere.
My first guess is to make sure that the “hidden” .htaccess file is there in your installation. Depending on your host and server, you might have to find a setting to make sure that you show “hidden” or “dot” files.
I copied the files from the omeka-s folder to another folder. I guess it didn’t copy the .htaccess file. Problem solved, thank you!