The verb is s'appeler - a reflexive verb form with the subject and object of the verb being the same. You can start to read here about pronominal, reciprocal and reflexive verbs:

 https://progress.lawlessfrench.com/my-languages/french/glossary/97

https://www.lawlessfrench.com/grammar/reflexive-verbs/

Vous means two different things here (confusing!). 

Vous appelez = you call/ you are calling e.g. "Vous appelez la police!" "You're calling the police!"

vous vous appelez = you call yourself (word for word, you yourself call), which we tend to translate as 'You are called'.

So, Vous can mean 'You' or 'Yourself'

And the second Vous has the same function in the phrase as the 'Me' in Je m'appelle or the 'Te' in Tu t'appelles. We can see the distinction between 'Je' and 'Me' because the words are different.

Hope this helps!

 Interesting process.  l think l like it.  Have been with duo lingo for  cinq cent et quatre vingt seize jours.

Do not like the political correctness, the subtle sermons.

Your inclusion of Shrove Tuesday, Ash Wednesday and accompaning music/celebrations is parfaite.