Whilst Schtum's reply may seem uncharitable I can't help but agree.
Admittedly getting to grips with the way that Garmin provide mapping updates isn't plain sailing which isn't helped by their instance on changing the way you're supposed to do it at least once a year. However, there is a wealth of knowledge on this site that should get you sorted. You need to approach the task in a calm and rational way. Your opening post is something of a rant and as such likely to dissuade some from offering to help you out.
The best approach would be to use the
older map updater rather than the rather fickle new kid on the block, AKA Garmin Express. The link is to the PC version.
Slowly go though the initial screens of the install, about the forth one in there will a an 'install options' button at bottom left. Clicking that will provide the choice of updating just the GPS, the GPS and PC or just the PC. It should recognise the fact that you have an SD card in your GPS and offer to install mapping there.
If all else fails just install to your PC and then use
MapInstall to put mapping onto your SD card, or the selected tiles that you need onto the Zumo's internal memory.
Water under the bridge but might help others reading this thread; Did you buy a lifetime update or just a one off? The lifetime update can be had from
Handtec for £50 which is what you pay Garmin directly for the one off update.
