To login to your website files using FTP, please follow these steps:

1. Download one of FTP programs like FileZilla, select open new connection.

2. Enter your domain name (domain.com) in the field (Host Address).

3. Enter your username in the field (User Name) and your password, FTP port 21.

4. Then press (Next) so that the program can check your connection to the website and if it’s finished successfully, the program will select the default folder of the website on your device. 

5. Press (Next) for the program to be connected to the website.

Note: You should upload all files within the folder public_html to show up to your website visitors.

IF you need to know how to create FTP account you can visit below Link.