*When 으로 is used after a place or direction, it is used as a directional particle. 앞으로 걸어가다 walk forward 부산으로 떠나다 leave for Busan *When 으로 is used after a way or mean, it is used as a instrumental or adverbial particle. 펜으로 쓰다 write with a pen 운동으로 건강을 유지하다 keep fit by exercising 약으로 병을 고치다 cure an illness with medicine 규칙적 is a way which means "regular" 규칙적으로 means "regularly" 식사를 규칙적으로 하다 eat regularly

The important part is actually 적. When you add it to some nouns, it is like adding -al or -ic to make words like cultural or scientific. Then adding -으로 to to that turns the word into an adverb: culturally, scientifically. You can also add -이다 (or -인) to 적 to make them into adjectives. Here's a good lesson on it: http://www.howtostudykorean.com/unit1/unit-1-lessons-9-16/lesson-16/