"I eat a meal."
Translation:Jeg spiser et måltid.
Et and en before a word are equivalent to "a/an". To mean "the" they are attatched to the word as a postfix (ie. "Et æble" = an apple, "æblet" = the apple). Most words take "en" (something like 80%) and you will unfortunately have to memorize which take et and which take en. When in doubt, use en. The odds will be in your favor.
Each noun has an article either et or en (in english that would be "the"). That's just something you have to learn word by word because it's pretty much random and there are no rules that work for every word.