I have fairly minimal 'bits-and-pieces' knowledge of LaTeX; I've only used it to write theses and technical documents. I want to use it to write a book, too, and in Word I designed the following chapter opening. I'm not asking for a fully-fledged code to produce this result, but some hints towards useful packages and/or documentation would be highly appreciated. The fncychap package didn't prove useful, neither did titlesec.
I'm using the memoir class, by the way.

titlesec, but I guess you'll need quite a bit of code to make it working like this. Would be interesting to know which class you're using, because some have their builtin methods to style headings. – Skillmon Dec 17 '22 at 19:46memoir. I was thinking of using a drop-cap style thingy to get that chapter number using a minipage or something, but I have very little knowledge of how to do that. – WalrusGumboot Dec 17 '22 at 19:52