Stage 2 - In the editor
First of all I will explain my basic project setup, Window Size: 1920x1080 - Layout size: 1920x1080.
The first thing you want to do is import your 3 sprites, your background, your select sprite and your placed sprite. Just put the select and placed sprites outside the layout (out of sight) and your background on its own layer.
BG - 1 sprite then lock. (0)
Main - main layer we're working with, our select and placed sprites should be on this layer. (1)
UI - Locked, we aren't working with this layer on this tutorial, always handy to have though.(2)
This is our layout setup. Now onto the code.