The definition of Tae Kwon Do is:
'The Art of hand and foot fighting and a way of life'
To put that in terms that students can understand. 50% of your life is physical and 50% is mental.
Which means we spend half our time practicing the physical parts of Martial Arts like the blocks, kicks punches, forms and we spend the other 50% learning the creeds, terms, principles and applying both of them to our everyday lives.
The information contained in the above links will assist with learning and applying the 50% mental.