The adverb broadly is useful for describing something that's done in a general or approximate way. If you're broadly describing your new job, you're giving just the basic idea of it and leaving out the details.
You're likely to see the word broadly within the phrase "broadly speaking." People often say this to mean "in general" or "on average." The word can also be used in a more literal way to mean "widely," as when you say, "The teacher seemed a little scary until she smiled broadly and welcomed them to class."