Assuming you would like a step by step guide on how to add an app icon to your home screen on a Samsung Galaxy device:
1. Find the app you want to add to your home screen. This can be done by opening the App Drawer if you're using a launcher, or by finding the app in your list of apps.
2. Tap and hold on the app icon until a menu pops up.
3. In the menu that appears, tap Add to Home Screen.
4. The app will be added to your home screen.