Inactive Recognized Developer
No videos that I am aware of, really. The basics are really simple, though:
Windows RT is just like normal Windows, except that
A) It's compiled for ARM, not x86 or x64.
B) It has kernel-mode validation which prevents launching programs or loading libraries unless either the binary has a Microsoft signature, or the program runs in a sandbox.
C) All devices which come with RT have mandatory Secure Boot, which prevents us from messing with the bootloader very much (for example, enabling kernel debug) or running any other OS on the devices.
The first is not really a problem; it just means that most existing Windows programs can't work unless re-compiled. .NET programs work un-modified. Java/Python/Ruby/Perl/PHP/whatever programs work as long as we have a working runtime for them. There's also a dynamic recompilation layer that somebody wrote, but it's very slow and not fully compatible.
The second is the biggest issue for most of us. The signature checks can be disabled via a finding a single kernel-mode memory write (this is how the jailbreak for 8.0 works) but without the ability to load our own drivers, or even to easily run third-party code as Admin, it's hard. 8.1 includes a bunch of extra checks to make it even *harder* (because really, that's what this OS needed... *more* customer-unfriendly lockdown!)
The third is an interesting problem in its own right, although most of us are fine running Windows (if we wanted Android, there are lots of options...) and just want a way to get past the signature checks. That would be relatively easy if not for Secure Boot preventing us from modifying the kernel itself, though...