S, O, and L are all one-point tiles. C is three points. H is 4 points. So, the word school would be a total of 11 points. More, if any of the letters are on bonus tiles, or the placement of the word creates additional words.
According to the tiles I have just pulled out of my Scrabble game they are scored as followed: A:1, B:3, C:3, D:2, E:1, F:4, G:2, H:4, I:1, J:8, K:5, L:1, M:3, N:1, O:1, P:3, Q:10, R:1, S:1, T:1,...
K=5 points. Depending on its position, 'K' score can be doubled, re-doubled, tripled or re-tripled and it can also carry the score of the word to which it will be connected.
The letter values are the little numbers on the corner of each letter and they are how many points you earn for using each letter. Make sure that you pay attention to the places on the board as well...