If you are just starting to learn programming and creating web pages, then the “Flexbox Cheatsheet” application will be a great helper.
You will know: how to arrange layout elements in one of four directions; how to determine the order of elements; how to properly center elements; how to determine their size; how to create equal height columns; how to align elements along the axis.
In the appendix you will find examples of placing layouts when laying out a page and the corresponding commands.