use all these 3 ports simultaneously to install other Operating Systems (e.g. another version of Linux OS)

Installation of Operating Systems in the PC/Laptop environment can be done in so many ways but  since we want to install another Operating System on the  15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid then this is the first method . This method is a fresh install of Linux Operating System on a  15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid .  Steps that we are going to take on how to install  Linux Operating  System (we take Linux OS Ubuntu 18.10 as an example) on a  15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid are :
  
1. we have to ensure that the  15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid  have  a   
 UEFI/BIOS (software/firmware) on the System Board .

2. we have to ensure that we have  3 units  of full-size  USB 2.0  or  3 units of full-size  USB 3.0  on the  15.6 inches  Linux Laptop/Tablet/Smartphone   hybrid .
Since we are doing a  fresh install of Linux Operating System  Ubuntu  18.10  on  the  15.6 inches  LinuxLaptop/Tablet/Smartphone  hybrid then  2 units of full-size USB 2.0  or  2 units of  full-size USB 3.0  should be sufficient . 
The first unit of full-size USB port (USB 2.0 or USB 3.0)  is  connected to an external DVD-RW drive so that we can insert the Linux OS Ubuntu 18.10 Live DVD to begin the software installation . The second unit of full-size USB port (USB 2.0 or USB 3.0) is connected to and external hard disk drive  or 
flash drive where the Linux OS  Ubuntu 18.10 will reside .
The second method involve hard disk drive cloning and we need to utilize 3 units of full-size USB port (USB 2.0 or USB 3.0)  simultaneously .  If we have a  external hard disk or a spare external hard disk that is already installed with  Linux OS Ubuntu  18.10  and we have another  external hard disk and we  want to install it on the  15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid , then  1 unit of full-size USB port is connected to an external DVD-RW drive (to insert a  a bootable Live CD like Clonezilla for cloning purposes) and the other 2 units of full-size USB port is connected to the SOURCE hard disk drive and the TARGET hard disk drive .
Note that for both method we use external hard disk drive and we use  Linux Operating System Ubuntu 18.10  .  Installation of other Operating System like  Linux OS  Ubuntu 18.10  or  Linux OS KNOPPIX 8.2 on the external hard disk drive which is then connected to the full-size USB port (USB 2.0 or USB 3.0) of the 15.6 inches  Linux  Laptop/Tablet/Smartphone   hybrid , does not override the existing Linux OS , which is residing , which is powering  the
15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid . 
With the presence of UEFI/BIOS on the System Board of the  15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid , we can select to  boot from  the  external hard disk drive or flash drive which has been installed with Linux Operating System Ubuntu 18.10  .  To the best of my knowledge , only Linux Operating System Ubuntu  18.10  and  Linux Operating  System  KNOPPIX 8.2  and other Linux variants can be booted from an external hard disk drive or flash drive with the help of  UEFI/BIOS .
Installation of other Operating System  like  Linux OS  Ubuntu  18.10  or  Linux OS KNOPPIX 8.2  on the external hard disk drive which is connected to the USB port  of  the  15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid  does not override the existing Linux OS which is residing  inside the  15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid .  The only snag when installing other Linux OS  is , the  15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid cannot make telephone calls and receive telephone calls , cannot send and receive sms , cannot WhatsApp , cannot WeChat , cannot Snapchat ,  cannot  Instagram , etc., etc.  After the other  Linux OS installation is complete and after we have finished doing what we want to do with the new Linux OS , just shutdown the new Linux OS .  Disconnect the external hard disk drive from the  15.6 inches  Linux   Laptop/Tablet/Smartphone   hybrid ,  reboot/restart the 
 15.6 inches  Linux  Laptop/Tablet/Smartphone  hybrid , then we can use the  15.6 inches  Linux   Laptop/Tablet/Smartphone  hybrid  just like an ordinary  Android  Smartphone ,  just like an ordinary Windows Smartphone .  Now , we can make phone calls , we can receive phone calls , we can send sms , we can WhatsApp , we can WeChat , we can Snapchat , we can Instagram , we can watch YouTube/Videos/Movies , we can connect to printers , we can connect to scanners , and a long list of everything the PC/Laptop/Tablet/Smartphone   can do ……..…….. we can also do with our  15.6 inches  Linux   Laptop/Tablet/Smartphone   hybrid .