Say you want to get somewhere else in XenClient. How would you do it? If you are currently inside a VM and want to switch to another VM, what would you do? One answer is to use the installed selector bar at the top. Another way is to know the keyboard shortcuts.
For switching between VMs and the Citrix Receiver for XenClient, just use the CTRL key with a number. Zero is for Receiver. One to nine are for VM slots. To switch from VM slot 2 to slot 1, just press CTRL+1. To get to Receiver, just press CTRL+0.
Most importantly, to get to a command prompt press CTRL+SHIFT+t. The command prompt is useful for understanding XenClient and getting to things that the UI does not have. For example, you can see the location of the VMs at /storage/disk with the VHD file extensions.
Otherwise it is necessary to boot XenClient in special mode to get access to the console. Or, you could use SSH to connect to XenClient if you know the IP address.
With any of these techniques you need to know the password for root which was specified during the installation.