You can use various methods to upload your website. The main method is by FTP.
1. By browser, see this article
2. By FTP, you can use any client, we have tutorials for CuteFTP & FileZilla
3. By a third-party web builder.
The important details you need for these are the:
1. Host: this is the IP or your ftp.domain.com;
4. Remote path: normally a forward slash.
These can be found in your welcome email.
Please be aware that you need to upload to the public_html directories, for example, if your username is demo and your domain is test.com, then you need to upload to /domains/test.com/public_html/
If you have more than one domain within your account, it is advised for you to create separate FTP logins for each domain pointed directly at the public_html directories. Please see our DirectAdmin Tutorials on how to do this.