You need a  Windows based FTP application loaded on your system.
(FTP applications like, Cute FTP, Terrapin FTP, etc., are some of the popular FTP client applications available.)
In our illustration, Cute FTP application is used to explain the steps of FTP process. Any application will have the similar parameters as explained.
You can download Cute FTP application from www.cuteftp.com
Following are the steps illustrated for Cute FTP:
Open Cute FTP application on your system
FTP Site Manager window will displayed, allowing you to configure your website for transferring files, as screen displayed below :
 

You will see, Add Host window displayed to give the details of the website to be configured. 

For example, if www.twincitiesbbs.com is the website to be configured, following are the details to be noted for configuring a website for FTP :

 
Site Label - This could be your website name (Eg: Twincities BBS)
 

Host Address
For every site an FTP account is created and the host address will be similar to
www.twincitiesbbs.com 

 
User Name and Password - Every FTP account will be given an User Name and Password.
 
The other options on the Add Host window can be left with default settings
Enter the mentioned details in the Add Host window as show in the below picture :
 

Click OK

Your website has been configured and the host site is listed for FTP.
To transfer files from the local system to the any particular directory on the host web server, Click on the Connect button on the FTP Site Manager as displayed in the following screen.
After authentication of User Name and password, you will be connected to the web server for transferring files in to respective directories. 
Following is the screen, that displays the directory and file system on your local system on the left hand side and the file and directory system on your web server on the right hand side.
You can observe the status of transferred files on the same screen.
 


Cute FTP is one, Client FTP application illustrated here. Similar applications can be configured with the given parameters.
 
You can upload files in any one of the following ways :
 
By clicking upload button on Cute FTP toolbar  or
 
By dragging files to the web server directory from the local system directory or
 
Select Upload option by right clicking the file to be transferred
 
Many options on this application can be explored for creating sub-directories, downloading, changing directories etc.,