In your Feed you see a list of popular lessons. Make sure to set your level in the Feed Settings and then scroll through your feed to find a lesson you like.
Once you have opened a lesson, you can see that lesson at the top of the Feed page in the Recent Lessons section.
Or, if you prefer, you can change to one of the other options on the Home page:
Getting Started - where you can take the 3 Beginner 1 courses to get you started
My Lessons - where you can find all the lessons you have chosen
New Lessons - where you can search and filter our full library of lessons