The basic thing for beginners to know what bitcoin is...
Before that, they would need to understand what the blockchain is, as it is the platform that allows the transfer of Bitcoin. In my opinion, there is no basic information, just bits and pieces that are learnt over time through reading and practicing.
The original white paper does was not intended for newbies but those with background knowledge on the blockchain technology.
The forum is a good place to start if you're looking to learn about Bitcoin. The Google search option provids loads of information at easy reach, you can also check out Reddit, YouTube, and some other useful social platforms.
I personally do not recommend articles by websites which are more often than not, promotional content, but there are useful information that can be learnt through them.