Windows RT ( and to some part Windows on Arm ) may look just like it's bigger brother, however they are built on different chips. So a virus for Windows PC for the most part will not work on Phone Windows RT and Windows on Arm. Much in the same way a Windows Virus can not attack an Apple Mac.
Now Windows on Arm will come from the shop with Windows 10 S, which means you will not be able to install any extra software on the device unless it comes from the Windows Store. So much like a Windows Phone, Android, and Apple iPhone you need a store to add.
Where this changes with Windows on Arm is you will have an option to turn your Windows 10 on Arm to Windows 10 Pro.
So then you can add what ever software you want, like an older version of Photoshop. However this could also mean because of the emulation in the software maybe a virus could run...I don't know that for sure.
However for at least a few years as Windows on Arm takes off hackers will ignore Windows Arm Laptop/Tablets as it would be too much work to make a virus and give little reward in return.
This is a very simple explanation but a full Windows on phone chips will be very very secure for a few years at least.
Now drivers on Windows on Arm will be different then on PC. On PC building a driver is much harder as a PC can come with any number of hardware bits, or a user can change the hardware and issues can pop up.
Windows on Arm, the hardware is set by Microsoft/Qualcom so the drivers are like a phone solid and just work, unless a bit of bad code gets out from Microsoft. However this does not happen as much as a PC user one day tries to change a video card and when he does a driver issue pops up and does not allow the PC to work.
From my own personal use of computers this has not happened to me since the days of Windows 98/ME. However I have also not built my own PC since then. I usually buy fully built as I am old and tired and I don't have the energy to trouble shoot issues.
I would not say your weak in terms of knowledge !!!!!! You started with a phone and are learning, you will then get a Laptop or PC or Mac or what ever and you will learn more. You are starting some where, many I know will not even learn how to send an email, they have a Smart phone to make phone calls only..........