Negations and negative expressions have a very important role in Swedish, but are also very easy to learn. You just insert the word "inte". If the word order is straight (noun/pronoun + verb), "inte" is to be inserted after the conjugated verb. In compound tenses, "inte" comes between the auxiliary and the main verb
Jag studerar svenska. (I am studying Swedish)
Jag studerar inte svenska. ( I am not studying Swedish)
Jag har inte studerat svenska. (I have not studied Swedish)
If the word order is reversed, (verb + noun/pronoun) in a question for example, "inte" is to be inserted after the noun.
Gör han det? (Is he doing that?)
Gör han inte det? (Isn't he doing that?)