I think it is something like chmod ... but after that i am lost
You mean website.
How are you publishing your website? what is the server you are using?
First of all is it working locally when you access the website. If yes then checkout in what port you are running the website. if you are running in default port 80 then checkout in the client system whether ports are opened in the Firewall.
chmod sets permissions.
What is the operating system? What is the webserver software (apache/lighttpd...)? Open port in firewall/router. Set path to webserver directly in the webserver config file.
Please give us more information.