Grids are a designer’s best friend, and anyone can use them to put together pages that look organized and cohesive.
The way to work with a grid is to break your page into small units. You combine these units together — while respecting the underlying grid — to create interesting pages that have variety, but look unified.
If that doesn’t make sense, it’s because talking about grids doesn’t communicate their power. It will make more sense to you if we look at some examples.