If you want to change your level of Words or Sentences, you have to:
1. Go to the "More" tab.
2. Tap on the "Courses" menu option.
3. Tap on the group you are learning.
4. Select the level you want to study.
You can do it both for:
Words
And Sentences
If you have a valid subscription (Premium or with flowers) you will be able to choose any level.
If you do not have a subscription, you will be able to choose just the first level.
How do I subscribe?
Can I subscribe without money?
How do I select multiple levels at the same time?