If wamp icon is green then Apache and MySQL have been started properly, tahts all the colour means.
WAMP 'Online' and 'Offline'
Wamp does not need to be online to work.
Offline means it will only respond to requests from IP Address 127.0.0.1 thats localhost ( and a security measure )
Online means anybody in the world can get to your web server .... ( if you have port forwarded your router )
So Offline is not a problem unless you are trying to access it from another PC inside your network.
Try using this address in your browser
http://127.0.0.1
If that works and you see the wamp home page then it is probably a IPV4 / IPV6 issue.
Report back and someone will help you solve that.
Also check your Apache error log ( also accessible from the wampmanager menus see what that is saying