I have a document and don’t want page numbering to begin until page 7.
So, let’s say my document is 10 pages long. Pages 1-6 I want blank, no numbering. Pages 7-10 I want to be numbered 1, 2 and 3.
I’ve been trying for ages (and all help I’ve encountered so far has been so over-complicated I can’t figure it out, and I’m no luddite!) and I can’t seem to do it.
Any advice please?
and all help I’ve encountered so far has been so over-complicated I can’t figure it out, and I’m no luddite!
Hum. Do you expect to be some secret kept from all except the chosen ones? 
I’m afraid that all you can get here is either references to documentation/other answers, or the same procedure repeated once again in other words.
In this question, I tried to explain the logic behind the feature, as I myself always feel comfortable knowing how it works inside. It wasn’t accepted. Then in this question, I tried to provide simple step-by-step guidance, not diving into underlying logic. No idea if you’ll find something useful there; bu it’s useful to ask specific questions.
I created an extension for this purpose, currently searching for new features to add. You can check it in LibreOffice Extensions here:
Page numbering are usually located in header or footer. Header/footer are attributes of page (more precisely of page style). When a page overflows, a new page is automatically started with the same style as the previous one.
If you want a different look for a page, you need a different page style so that you can define different attributes. You must also insert a break to force switching to the desired page style.
@mikekaganski’s procedure in his answer provides all the necessary steps.
Go to Format > Title Page and set the number of pages you want without numbers on at the beginning of the doc. Set Start Numbering at whatever number you want.