Follow the same steps as before but instead of Crystalline Creatures put in GeckoLib.

Once the search has loaded, GeckoLib should be there. Open the mod project and head to the next step.

Now, as my mod only has one version so far, you need to find the mod file for 1.20.1 Forge in Gecko Lib and install it.

On a new tab search up Java Install and find the respective page for your OS from Java.com. For this tutorial it will be Windows as the OS.

Once you opened that link, you should be on a page similar to this.

Click the green Download Java button and the download should start. Once downloaded open the setup and go through the details.

On a new tab search up Forge Mod Loader and the first website should be a Minecraft Forge website.

Once you opened that link, you should be on a page similar to this. On the left hand side, there should be a list of versions. Click version 1.20.1. There should be two installers, click the recommended one.

 After clicking an installer, it will redirect you to an ad page, click the skip button and the mod loader should begin to download. Open the file for Forge and go through it's setup.
*Disclaimer: Do not click anything on this page that is not the skip button on the top right in red. Anything else may lead you to virus or malware pages.

Open Minecraft Launcher, there you will find a new installation called Forge.

Press play on that installation and wait for it to load.

Once Minecraft has loaded, there should be a mods tab.

Click the mods tab and then click open mods folder.

When the file explorer opens, drag in the two downloaded files, Crystalline Creatures and GeckoLib, into that folder.

Once done, the Mod should be ready to go!