Goals are a powerful way to direct your energy and determine what you want to achieve in life. Unlike tasks, which have a clear path of action, goals are intangible and difficult to quantify. Once you set your goals, you can keep track of which tasks contribute to these goals, see the number of completed tasks that contribute to each goal and measure your progress. Goals can be long term life goals (like "retire" or "build my dream home"), or short term (like "pay off car loan").
Goal Chains are a visual way to see the number of tasks that you have completed for each goal, as well as the goal's chain. The chain gets longer for each consecutive day that you do a task that contributes to the goal. If you make progress on a goal each day, you will have a long chain. If you miss a day, that chain will get broken. Try not to break the chain. This is a good way to motivate yourself to work on your goals.