Update 1-1-1-create-vm-oracle-virtualbox.md to clarify Ubuntu Server should be...

Update 1-1-1-create-vm-oracle-virtualbox.md to clarify Ubuntu Server should be use instead of Desktop

tutorial/1-1-1-create-vm-oracle-virtualbox.md

@@ -26,7 +26,8 @@ __Note__: IP address 10.0.2.10 is the one that will be assigned to the VM.
 - RAM: 8 GB
 - Disk: 40 GB, Virtual Disk Image (VDI), Dynamically allocated
 - Optical Drive ISO Image: "ubuntu-20.04.4-live-server-amd64.iso"
-  (from [Ubuntu Server 20.04 LTS](https://releases.ubuntu.com/20.04/))
+  - Download the file "ubuntu-20.04.4-live-server-amd64.iso" from [Ubuntu 20.04 LTS](https://releases.ubuntu.com/20.04/).
+  - __Note__: use Ubuntu Server image instead of Ubuntu Desktop to create a lightweight VM.
 - Network Adapter 1 (*): enabled, attached to NAT Network "TFS-NAT-Net"
 - Minor adjustments (*):
   - Audio: disabled