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.
Layers
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.