Knowing a little bit about sports and horse racing can be an advantage, but it is definitely not required. You can learn bit by bit following the guides to the letter and learning new things. In terms of choosing the right things to bet on, this is less dictated by your knowledge of the teams playing or the horses running and more by what bet has the best odds for matched betting.
Check out my review of Outplayed or to give matched betting a try head over for the free trial.