Importing it into BakkesMod

1. Download BakkesMod.
2. Download the AlphaConsole plugin.
3. Download the zip file.
4. Open BakkesMod > File > Open BakkesMod Folder > data > acplugin > DecalTextures
5. At the top of your File Explorer click on the file path and CTRL + C to copy it.
6. Open a New File Explorer window and extract your Zipped Decal Folder. Make sure to paste the file path to the "Files will be extracted to this folder" field with CTRL + V.
7. Launch Rocket League and use F2 to open the BakkesMod console.
8. Go to the Plugins tab and uncheck AlphaConsole. After a few seconds recheck AlphaConsole.
9. Press F5 to open AlphaConsole. and if you see a warning message click Disable Safe Mode.
10. Go to the Cosmetics tab and find Decal Texture Mods.
11. Select the option for either Blue Decal or Orange Decal and select the desired decal from the list.

For more detail go to this video.