This CSS grid generator can help a beginner create a simple grid by providing information about how many rows and columns they want as well as the gap between each. Developers can use the GUI to tweak the size of each row and column as well. After customizing to their liking, they can view and use the code that was created.
The CSS-tricks guide is a more comprehensive resource that includes all of the properties for the grid parents/containers and items within the grid. This resource will help a developer get started using the basics of grid and can also be referred to when trying to do more complex developing with grid. This guide is a very helpful reference when developing grid layouts.
As always, the Mozilla Developer Network provides an all-inclusive list of grid properties and information on how to get started with grid. Each property has its own page which goes more in depth on the specific property. There are examples and diagrams to help visualize what each property does.
Understanding all of the different layout options with CSS grid can be tricky, but there are countless resources to help. From interactive generators to comprehensive documentation of the different properties, there is no shortage of information available.