How does class n_columns work

I am struggling a bit getting several items next to each other. Everything beyond to graphs seems to now work.
I was looking for some more info on stylesheets and in particular on classes and what how in the default style sheets those classes like five columns work.
Does anyone know a good resource or a brief summary?
Thanks

I recommend just reading through the stylesheets themselves. Columns in particular is only a few lines of CSS. You can play around with the css and the html in this codepen sandbox: https://codepen.io/chriddyp/pen/dZVMbK

Thanks. I will have a look and see if I can learn from there