Translation:There are many tall houses around this square.
Not in the app.
They're only available on the website -- and they might only be displayed if the website thinks your screen is big enough (on a smartphone, the website may appear like the app, complete with lack of lesson notes).
Your best bet is probably to read the lesson notes on a computer before starting a new lesson.
a tér - the square
a tér körül - around the square
ez a tér - this square
e körül a tér körül - around this square
When you apply a postposition to a noun with a demonstrative this/that/these/those (ez/az/ezek/azok) before it, the demonstrative also has to receive the postposition.
Additionally, the adjectives ez and az lose their 'z' when they are followed by a consonant like this.