Most probably your FTP would be already setup with ur account. To access ur account with FTP. Just download any of the FTP clients. Like smartFTp, FILEZILLA, etc.,
and enter the required information
1) for the HOST address type: ftp.yourdomaindomain.com, username and password would be same as the control panel
2) thats it. you are ready to go.
If in case ur FTP account was not ready, ask ur web host to give the FTP details to you. He will surely give you and you may start uploading your site details on your server. Its not actually that hard. Good luck.
ciao