This is arguably the most essential script for any active player. Instead of manually clicking on dozens of barbarian villages, a farm assistant script allows you to send pre-set troop loads with a single click from the map view.
At its core, Tampermonkey is a tool that allows you to run small pieces of JavaScript code (user scripts) on specific web pages. For Tribal Wars, this means you can modify the game's interface, automate repetitive tasks, and add information layers that aren't available in the standard client. The official Tribal Wars team itself acknowledges this, providing guides on how to install and use Tampermonkey to run approved user scripts.
First, install Tampermonkey from your browser's extension store (Chrome, Firefox, Edge, etc.).