The majority of the time there are spaces between Korean words. I've noticed that some places where space is a premium, or because of typing using some phone keyboards, there aren't always spaces between the words. I usually find this on Twitter (SNS), Kakao Talk; and some children's book titles I have don't have the spaces between the words. If you look inside the books, or read newspapers or webtoons, there are spaces in between the words.
The Korean language does indeed use spaces.
You know where one word starts and ends through the use of spaces and knowing grammar and particles.