Install instructions? Stick the disk in and off you go! Well, with fingers
crossed anyway. But if it's your first time with Ubuntu you'd probably do
well to keep Windows running side by side until you're sure Ubuntu can do
everything you need. Dual booting initially worked well for me, and
providing there's enough disk space should happen almost automatically.
There are other options such as emulation or virtualization, and of course
if you've got other computers to run Windows then throw caution to the
winds.

And come back here if you run into difficulties. Chances are ubuntu will
run straight up and delight you, but sometimes there are oddities, but if
so you can be pretty sure someone will have solved them.

OpenOffice comes with Ubuntu (or if not for any reason then you can get it
from the repositories once Ubuntu's up and running). It will replace Word
and Excel and I think PowerPoint with close to 100% compatibility. Macros
is probably the most incompatible part - I think you have to start again
if you have any of those. Access is another matter though. There is a
database manager but I haven't been able to find any points of
compatibility in it - not that I've looked very hard. But it's one of the
few things for which I still have to put up with XP. Incidentally you can
also get OpenOffice on Windows - for free - and if more people did so then
microsoft might get the message that they can't charge big bucks for new
software that breaks what its users have already done with it.

The job of Windows Explorer is taken in Ubuntu by Nautilus by default
(Dolphin in Kubuntu), but as in Windows you hardly notice it, it fires up
when you try to browse for files. There are subtle little differences from
Windows but you soon get used to using it. Firefox 3 is the internet
browser by default in Ubuntu (Konqueror in Kubuntu but it's easy to
replace it with Firefox). Evolution handles Ubuntu email by default, I
thought it was good enough but a bit drab. There are plenty of
alternatives, I've found Thunderbird suits my way of doing things, even
though it's fairly similar to Outlook. MS Outlook won't run, no Windows
exes will, but there are replacements for almost everything, and if you
just can't find what you need you can run many exes in Wine, which
emulates Windows, or as a last resort install VirtualBox to run a minimal
Windows within Ubuntu. That's what I use for my heavily asp and access
bound website, and my CorelDraw graphics, until I can find the time for a
complete rewrite.

I still consider myself quite a newbie to Ubuntu, although I've been
playing with it for a couple of years and gradually had more and more
successes. Like many here my computing experience goes back decades, and
like you I still surprise myself by just how much I don't understand.