The Software is freely available as Open Source Software under the terms of the GNU General Public License (GPL):

https://www.virtualbox.org

It is easy to use, after the installation, you can create a new Virtual Machine:

Installation & Setup

• Machine > New
• Give it a Name and select the path (or default recommendation)
• Select the Operation System you plan to install
• Download an ISO, e.g. Microsoft Windows from Microsoft Webpage, or a Linux Distribution, e.g.
  • Linux Mint
  • Ubuntu
  • more at Wikipedia

• Select the Memory (check the recommended requirement for each of the OS), click NEXT
• Then you will have to create a Virtual Hard Disk, click CREATE
• I would recommend to use the Default ‘VDI’ Hard disk file and NEXT
• I usually select ‘Fixed Size’ as I just use it for testing. and NEXT
• Select the Disk Size (recommended or if you have enough space a little bit more) and CREATE

After its created, you will need to install an Operation System (links above)

• Select your created Virtual Machine, and ‘Settings‘
• Click on System, and under Motherboard, I usually remove the check mark for Floppy.
• Adjust the Base Memory, the right side should show your max computer Memory, so don’t go into the red, but if possible increase it, that will speed up a few things when running the OS.
• Under System click on the Tab ‘Processor‘ if you have a machine that has a powerful enough CPU why not share another Processor, but don’t select all because then your hosting computer may will have some speed issues. Confirm with ‘OK’
• Click on ‘Display‘ under Settings, same like previously with the Base Memory, if possible and needed give the Virtual Machine a little bit more Memory. Confirm with ‘OK’
• Storage – Here you can insert the downloaded ISO of previously downloaded OS so that you can start installing the Operation System. Click on the ‘Empty’ Disk Icon and on the right there is a little disk when you click on that, you can choose ‘Choose a disk file’ here select then the ISO you want install.
• Next you can ‘Start‘ The Virtual Machine and it should load up and show the OS Installation Screen, after the installation, the VM will reboot and next time with the start up, it should show you the Operation System loading. Good luck and have fun.