Check out example codes for "what are the units used in css grid". It will help you in understanding the concepts better.
Code Example 1
the units used in css grid are as follows: 1) fr: sets the column or row to a fraction of the available space. 2) auto: sets the column or row to the width or height of its content automatically. 3) %: sets the column or row to the percent width of its container.
Learn ReactJs, React Native from akashmittal.com