Combining layout grids in Figma lets you make complex designs easily. For instance, using both column and row grids together gives you more control over how things line up both up and down and side to side.

Here’s how to do it:

1. First, pick the frame you want to add grids to.
2. Then, click the + next to Layout guide in the Design panel.
3. Choose the type of grid you want by clicking on the Layout guide settings icon.
4. Set any other properties you need for your grid.
5. If you want to add more grids, just repeat these steps to add them.

This way, you can line up your design elements perfectly, making your project look neat and professional.