To set up FTP access to your websites, you have to -
1. Install your choice of an FTP Server, such as FileZilla (a popular one), on the same system that the WAMP server is on.
2. Using the FTP Server:
A) Create an FTP user account with full read and write permission granted on your website’s \webroot (DocumentRoot) folder.
B) And set that folder as the FTP user’s home-folder.
Then to take care of everything else -
1. Port-forward the FTP port in the Router to the LAN IP address of the server (if you are behind a Router).
2. Open the FTP port (for incoming connections) in Windows’ Firewall application.
The FTP port is 21.
The remote FTP user would then login on the WAMP server’s IP address (Public IP) or website’s domain-name (if the domain is registered and reachable) using his username + password credentials, and will have access to the specified home-folder.
* Everything related to FTP would be done via the FTP Server, and not the WAMP server.
* WinSCP is a good FTP client that can be used to connect to the FTP server.