In addition to the sibling you might like: https://cssgridgarden.com/

Maybe start with MDN?

https://developer.mozilla.org/en-US/docs/Learn/CSS/CSS_layou...

https://developer.mozilla.org/en-US/docs/Web/CSS/grid

I found watching Kevin Powell's intro on YouTube really helpful. I already had a basic understanding of grid before watching it, but this helped me make sense of the snippets I'd pieced together in my brain over the last couple of years.

https://www.youtube.com/watch?v=rg7Fvvl3taU

Wes Bos has a freebie

https://cssgrid.io/

CSS Tricks also has

https://css-tricks.com/snippets/css/complete-guide-grid/

The official spec is quite good.

See csswg