Read how to create a collection view that will be working in iOS 13 using SwiftUI, without using the tools available to make grids in iOS 14+.
Creating Grids in SwiftUI
Read and learn in this post how to create vertical and horizontal grids in SwiftUI, as well as how to combine them for great visual results.
Working with Collection Views on macOS
Learn how to add collection views on macOS projects and how to display collections of data with that standard control.