So you need to get to your site files. We've made connecting to your server simple, either use SSH (guide here) or FTP. You need to download and install an FTP Client (Filezilla works well and is free). Once installed here's a step by step guide on how to connect.
The Quickconnect bar along the top contains all the default settings that you need to connect and you can get the details to populate the fields from the Nimbus Hosting platform. We've got some instructions on how to get those details here. Enter the Host, Username and Password and then click Quickconnect.
You may see a message about the certificate, press ok.
The connection is made and you will see the files on the remote server on the right pane.