The reader is where you study your lessons. Play the audio using the player at bottom. Swipe right to move to the next page in the lesson and left to come back.
When you first open a lesson all new words are blue. This means you have never seen them before on LingQ. You should tap on all blue words you don't understand. When you do, you will see some popular translations to choose from or you can check a dictionary to create your own translation. Once you choose a translation those words become yellow "LingQs". These are now going to show as yellow in all future lessons and you can review them using the Review Activities.
As you page, all words you have left blue will be considered known and turn white. You will only be left with white and yellow words. As you review this lesson and study future lessons, you will see your LingQs in multiple contexts and you will gradually learn them this way. As you learn them, increase their status until they become Known.
Don't worry if you accidentally swipe a bunch of blue words away. You can always tap on unknown words to make them blue and LingQ them as you read. Over time you will see your Known Words number moving up and up!