Create a new scene with Control as the root
Add a TextureRect as a child
Set the Texture to Inventory_style_01b.png
Set the Texture Filter to Nearest
Select the TextureRect node
Add a GridContainer as a child
Rename it to MainInventory
Position and Resize over Main Inventory
Select MainInventory Node
Theme Overrides => Constants
Select the TextureRect node
Add another GridContainer as a child
Rename it to BeltInventory
Position and Resize over Lower Inventory
Select the TextureRect node
Add another GridContainer as a child
Position and Resize over Left Side
Position and Resize over Right Side
Add a TextureRect as child of MainInventory
Set the Texture to New AtlasTexture
Click on AtlasTexture to expand it
Set the Atlas to #1 - Transparent Icons.png
Set Snap Mode to Auto Slice
Choose an icon to display
Set Expand Mode to Ingore Size
Set Custom Minimum Size to 16 x 16