Where are the lessons En la farmacia (A2)

Question

Hello, hope you are all well.In this exercise the link that says (lesson) brings us here, however there is no lesson, nor any explanation as to the use of this particular phrase and another one below.  I did a search of these terms, but nothing came up.I have two errors, that I would like to understand why they are errors to learn from them, i.e.this one "Me hacen falta " and the one of " "aquí es la tarjeta:. (see below text)CLIENT: I need two, one for me and one for my father. CLIENTA: Me hacen necesidad dos, una para mí y otra para mi padre. CLIENTA: Me hacen falta dos, una para mí y otra para mi padre. "CLIENT: Here's the card. Thank you.CLIENTA: aquí es la tarjeta. Muchas gracias.CLIENTA: Aquí tiene la tarjeta. Muchas gracias.I looked for a comment in the exercise itself, but there was none, so I am writing this here.Thank you for your help and stay well.Nicole

Answer

Hola Nicole
With exercises testing just vocabulary about a specific topic (in this case, "going to the chemist") the links are not to lessons but to that specific word you got wrong or sometimes a phrase. It will give you the translation to that, only, not an explanatory lesson. This is all about learning specific vocabulary.
With reference to your two incorrect answers, 
1. "Aquí tiene ... " is the idiomatic phrase used when you go to the shop (in this case the chemist) and say "here is the money" , "here is my card" "here is the change". We don't use the verb "ser" like in English (here is...) but the verb "tener". 
2. "Me hace/n falta" is another idiomatic phrase to say "I need". It works the same way as "me gusta/n". 
Here is the whole studylist related to this exercise if you want to have a look.
I hope this helped.
En la farmacia (vocabulary)
Inma

Answer

Hola Inma,Muchas gracias,Nicole