To me, a Library is a database. It's where I keep (reference to) all of my stock footage and music/sound effects on my "system" (9 external hard drives). It is, IRL, just a text file that keeps track of everything you need to use for your video production(s). [For the record: you can keep as many Libraries available inside Final Cut as you want, or need... and navigate between them from within the application. I usually only keep one Library loaded at a time, unless I need to move material from older libraries into the new one.]
An Event, again, for *me*, is usually a span of time that I spend working on various ideas (I am a template developer) — example: Jan-Mar 2025 is something I'd name an event. Events help me keep ideas organized in time. If I need to look something up, I can find the timestamps any exports or templates I've developed and immediately go to the Event I was working in when the videos/templates were produced.
I also use Events to organize my Stock footage and audio clips with further subcategories created with Keyword and Smart Collections. For example, I have ALL stockfootage in a Stockfootage event and Smart Collections automatically arranging footage by Aspect ratio as well as Frame Rates and Keyword Collections organizing all the stockfootage by source (e.g. Pond5, Pexels, Mixkit, etc. etc.) so I know right away to whom to apply screen credits.
A Project has different purposes, depending. I have to develop templates that work in various video aspects: 16:9, 9:16, 2:1, etc.. etc.. etc... so I'll create projects with those aspect ratios for testing. I occasionally need to test various templates in different frame rate scenarios, so I'll create projects for each frame rate. Projects can become long (more than an hour) of just raw footage for testing and staging. Videos produced tend to be products of a subsection of a project varying from about 30 seconds to several minutes demonstrating new templates. These are typically Demo/Tutorial videos for products under development. Subsections are exported using the Range tool — no need to export an entire project when it's not needed or make another project that's just the material to be exported.
It took me less than a week to learn/accept/master the Final Cut interface. I had a head start — the Final Cut Pro X UI is (IMO) based on a piece of software that came out in the 1990s called HyperEngine-AV (by Arboretum Systems) which was the first "trackless" video editing software I ever came across and I had used for awhile. (No coincidence that FCPX came out about 6 months after HyperEngine-AV became Open Source software???)
The fact that you even mentioned Vegas means you're coming from the Windows platform — I'm sure that is contributing significantly to your inability to quickly adjust to the Apple way of doing things. There have been a wide variety of suggestions in this thread on using Final Cut. It is a testament to the huge amount of flexibility the software offers video producers with so many different kinds of workflows.
To me: Final Cut Pro is a *playground* and/or a laboratory for all kinds of experimentation. I definitely use it in different ways than most will and I'm "in it" every day.
No video was used in the production of this still created in Final Cut Pro (just previously made Motion templates and made after I wrote the above and just before I sent this post...corny as it is):
