How to transfer data to/from cluster?

You can use any SFTP client you like.

The guide will be based on FIleZilla FTP client

First, download FileZilla client from here. 

 Run it.

Open the Site Manager

Add new site (for example @MEiL Cluster)

Fill all the fields as shown below.
To load your private key, click and point to it.

 

After successful connection you'll see a remote server content in right window.

Now you can simply drag & drop files from one window (local disk) to another (remote server) to copy files.