Trying to create a web component Library in Vanilla JS, How would you start?

I am a girl who is new to programming, and want to create a small buildable library in vanilla js with buttons with and without loader for example, for start... and later add some forms, image sliders, and such

I am a little confused as to what I actually need to build a reusable components, how do I make it into a library that's accessible to my team and how to implement the components into real pages.

Can someone "explain like I'm 5" what steps I should take? There are many tutorials using react and angular, but I would prefer no framework for now.

Thanks in advance for any help :)