Yes that’s the one.
The easiest way to learn these is to set up a codepen with the bootstrap files in place (in the settings of codepen) and then copy the grid html snippets and play around with them to see how they work. You can put your custom css in the css panel of codepen and then you will soon learn how to make it do what you want with regards to the column grid.
Actually just fork my codepen below from the button at the bottom (once you’ve opened a free account) as it has the files in place.
You can remove the html and try your own or just try and modify what I have in place already.