There are two methods which you could use to connect. The second is mainly used if the first method does not work.

You can download FileZilla from Here 

Method 1:

Open Filezilla and enter your FTP username and password using the Quickconnect option.

Host: ( would be your domain name)

Username: Your FTP username

Password: Your FTP password

Port: You can leave this section blank as it will automatically make use of the default port.

You might receive a popup message referring to the certificate installed on the server. 

You should be connected to the server successfully and you are now able to drag the files from your PC onto the server (Files from the left window to the right)

Method 2:

If the first method fails then you can try connecting to the server by following these steps:

Click on "File" found at the top and select "Site Manager"

Click on New Site

This will allow you to edit the information on the right hand side.

You should be connected now to upload your website content.