tl;dr: It's a tetraquark, not a fundamental particle. We've seen tetraquarks before, just not one made out of four charmed particles. And it's not 100% clear that it's actually a tetraquark rather than two mesons.
Better link: https://home.cern/news/news/physics/lhcb-discovers-new-type-...
2019: CERN Pentaquark found (7.3 sigma)
https://home.cern/news/news/physics/lhcb-experiment-discover...
https://theconversation.com/exotic-particles-containing-five...
How many particles can be made of other particles? Stay tuned!
> The paper by more than 800 authors is yet to be evaluated by other scientists in a process called “peer review”
"'Peer review'? Hey Professor Einstein go easy on the technical terms. We're only human here!"