1. Open Filezilla
2. Go to Site Manager
3. Add New Site
4 Enter Domain name in Host
5 Port : 21
6. Protocol : FTP
7 Encryption : Only use plain FTP
8. Login Type : Normal

User: Enter cPanel Username
Password : Enter cPanel password

Now Click on Connect

At right hand side it will show you folders of server side.

In case of linux hosting, you need to upload your files in public_html folder

in case of Windows hosting, you need to upload your files in httpdocs folder.