'en' is not 'it'.
It has two main functions.
As a pronoun, it replaces a number or a de conjunction. For example, if someone asks you, "Tu veux du yaourt?" (Do you want yogurt) rather than saying "Non, je ne veux pas du yaourt." (No, I don't want yogurt) you can replace 'du' with 'en' and say "Non, je n'en veux pas." (No, I don't want some.) This makes it so you don't have to repeat yaourt.
Number-wise, if someone asks you "Tu manges beaucoup de sandwichs?" (Do you eat a lot of sanwiches?) rather than saying "Oui, j'ai mangé deux sandwichs" (Yes, I ate two sandwiches) you can respond "Oui, j'en ai mangé deux. (yes, I ate two [of them])
It's other function is as a preposition. If the place/conuntry is feminine (such as 'la France') you use 'en' to say 'in' or 'to' that country.
For example, "J'ai voyagé en France" (I traveled to France) is the correct form, along with "J'ai fait des magasins en France" (I went shopping in France)
As a side note, if the country is masculine, then you use 'au'.
If you have any other questions, just ask! :)
I speak French