Step 1. Install Optifine
Download Optifine through optifine.net/downloads (we used HD U E3 for Minecraft 1.12.2 in our testing), DO NOT open this file, instead, click on the "plus" button on the main menu of A Tale About Nature, this should open your mods folder, cut and paste the Optifine file in to this folder and restart A Tale About Nature.
Step 2. Install Sildur's Vibrant Shaders
Download the shaders through www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-mods/1291396-1-6-4-1-13-2-sildurs-shaders-pc-mac-intel-vibrant (we used Sildur's 1.19 Lite in our testing), navigate to the shaders menu located after video settings, and open the shaders folder, cut and paste the shaders in to here. You do not have to restart Minecraft, instead, just select them, we recommend doing this only on the main menu for lower end computers.
Advanced Step: Set Up Streams Support
Navigate to the "addtoshaders" folder in your ATAN installation and copy and paste the block.properties file that is located in there, unzip the shaders you downloaded and locate their version of this file, then, replace it with the one included with the pack, rezip the shaders if needed and enjoy!