I quite hard to have a single webpage with the most concise information. Why? Not because we cannot "compress" all the Bitcoin info in very specific and simple aspects, but because:

I am telling you this because all these 10+ years I was onboarding nocoiners and I know how they think. Make your own material, webpages, flyers, speeches, where YOU are comfortable to talk. Don't just repeat what others said. YOU MUST know (almost) everything about Bitcoin in order to be ready to orange pill somebody, because they will come with many questions and if you do not know the answer... you lose them and you fall into disgrace for them. MARK MY WORDS. YOU are the responsible for that new bitcoiner !

You can start with the resources I linked on my main substack page:

Then go on and read and understand for yourself these, then start teaching them:

... and many other guides from my substack (see my SN bio)

For complete no-coiners, I started my niece and nephew (recent uni graduates in engineering) with a $BTC gift through Cashapp and asked them to start a small regular automated (DCA) purchase. I then started forwarding them good beginners info from social media. The nephew immediately converted to fiat and spent his gift. The niece, within a month asked me about a wallet to move her coins off Cashapp. She has been buying regularly since Christmas 2021. The nephew will get the price he deserves.

The best way I have found to onboarding a no-coiner is with the Padawan wallet. It uses the signet network for test coins, and has brief tutorials. https://padawanwallet.com