Grammer- Dans ou En

Question 1

Dans

Answer 1

For a time limit in the present or the future (in a time limit - in an hour, I will be there - Dans une heure, je vais arriver); something that occurs in a decade; use dans when you want to say “in” something but the something takes an article
(dans “le” maison not en “le” maison)

Question 2

En

Answer 2

For a time limit in the present or the past (within a time limit - we finished in an our - nous aovns fini en une heure); express month, season or year something takes place in; use en when you want to say “in” something and the something does not take an article (il est “en” class not “dans” class)