How can I "correctly" download a website "only" and no other sites. Let me
explain.

So I have the following address (example)

<http://somesite.com>

My first question is this - should I add www. to it?
The next question is inside "Set options"

I clear everything under "Scan Rules"

Now what should I put there to download everything including all files on the
site (even those that are external), but NOT everything on the external
sites?
I tried

+somesite.com/*
+*
+*.*

on 2 lines, and immediately found out it was stupdid. So I know that much.
However, all my configurations lead to endless downloads, even on small
websites. So what is the basic setup I should use for downloading a website
with all data and files and not accidentally end up downloading the web?