Prism Launcher

1. Open the Prism Launcher

2. Click on the Modrinth tab on the left

3. Click on Fabulously Optimized

4. If you do not want the latest version, select the version you want from the dropdown

5. Click on OK. Once installed, you should see something

6. Double-click on the icon to play. Minecraft should open up

7. If you can see Fabulously Optimized in the bottom-right corner, you're done!