What does this advice given to me actually mean?

I am new to all of this

Can't really give you much advice without context or at least some background information.

Links refers to backlinks which are links from other sites to your site. Google uses backlinks to assess your site for SEO purposes. The more authoritative the linking site, the more value googles gives to the backlinks pointing to your site.

Rankbrain is the name given to the machine algorithm that evaluates urls for seo.

The last bit is he is saying he embedded links in fake science papers that are then uploaded to repositories that get good SEO juice from Google because of the authority given to the repository.

Were those your questions?

"rankbrain or whatever its called" looks like solid advice from someone who doesnt even know what hes talking about lol

I agree with your guru about links but not the other part.

Getting links from education resources is more beneficial for E-A-T rather than feeding RankBrain imo. They can simply be strong links, hence the rankings.

Backlinks, just like RankBrain are 2 of many signals search engine uses to sort their search results.

RankBrain is a machine learning AI that is part of the overall algorithm - Hummingbird. They claim RankBrain is the 3rd most important signal.

We don't really know what is #1 and #2 but there are strong indications #1 is backlinks and #2 in on-page or more specifically words on a page.

Backlinks - pages on web giving vote for your page
On-page - elements of the page search engines use to understand content and context
RankBrain - (my understanding) algorithm that helps identify true intent behind search query