Experience points are points you gather by working on your videos on EnglishCentral. Experience points reflect your effort in your online learning.
In the header on the EnglishCentral webpage you'll find the 'My English' section. Here you can view your progress box. In the EnglishCentral apps, you'll find the 'experience points' button. It's the yellow/orange round button with a star. By clicking the button, you'll be able to see:
1. How many points you have collected so far
2. How many points you have gained in the past seven days.
Short answer: as much as possible!