Mozilla provide a fantastic resource for designers and developers in this step through introduction to CSS Grid Layout.

In this 10 part guide you will be guided through:

• Terminology
• Your first grid
• FireFox DevTols
• The fr unit
• Mixing units
• Position items
• Basic layout
• Template areas
• Named lines
• More to learn

Head over to Mozilla to view this awesome guide

https://mozilladevelopers.github.io/playground