Sophos XG API

As per this article:https://doc.sophos.com/nsg/sophos-firewall/18.5/help/en-us/webhelp/onlinehelp/AdministratorHelp/BackupAndFirmware/API/APIUsingAPI/index.html

is seems i can get the ip host objects if i can do something like:

1.1.1.1:4444/.../APIController admin</Username><Password>abcd</Password></Login><Get><IPHost><Name></Name><IPFamily></IPFamily><HostType></HostType><IPAddress></IPAddress></IPHost></Get></Request>

Those articles are note very helpful:

https://doc.sophos.com/nsg/sophos-firewall/18.5/help/en-us/webhelp/onlinehelp/AdministratorHelp/BackupAndFirmware/API/APIUsingAPI/index.html#get-add-update-or-delete-an-ip-host

This provides a very useful way of doing some things in an programable/automated way.

https://docs.sophos.com/nsg/sophos-firewall/18.5/API/index.html 

But i need to start with the basics:

How do i get the objects and how do i know where they are located?

for example the following should retrive the firmware version:

<Request> <Get> <System> <FirmwareVersion/> </System> </Get> </Request> </Request>

however i get: