Please can someone tell me where I can go to read about what "lingots" and "goals" are and how they work. I cannot find these instructions anywhere.
This information can be found in the shop: "What is a lingot? A lingot [ling-guht] is the Duolingo virtual currency. The more you learn on Duolingo, the more lingots you'll receive and be able to use in the store!"
You can go into the shop for more information and how to spend lingots.
A goal is an amount of Duolingo experience that you try to earn every day. You can choose how big you want the goal to be, I think anywhere from 1-50 experience. Duolingo tells you how close you are to meeting your goal each day and I think you get lingots as a reward for meeting it.