Aside from uploading the web files via FTP , you will be able to also upload your webfiles from your WordPress control panel.

1. Login to your WordPress control panel via our client area portal. 

2. Click on "Files" on your left sidebar and you will see the upload screen shows up.

3. To upload the files on the current directory, click on the "Upload" and select the files (you can select multiple files). Example, to upload to the httpdocs folder, double click into httpdocs folder on the right panel, Click on Upload, and select the web files on your local drive and upload.

While you can do the uploading via the control panel, doing via FTP upload would be a much-recommended option.