The Rules of Sudoku
The rules of sudoku are very simple and can be explained in one sentence :
Fill in all empty cells with numbers from 1 to 9, so that they don't appear more than once in each row, column and inside 3x3 block.
No need to be a mathematician. Logics alone should be enough to solve the puzzles.

Sudoku puzzles are divided in 9 rows, 9 columns and 9 blocks.
Each of them must have all numbers from 1 to 9.
Each
cell
must have a number from 1 to 9. It belongs to 3 groups :
it is part of a row, a column and a 3x3 block.
Elements which must have all numbers from 1 to 9 are called sets :
 A row is a group of nine cells setup horizontally
 A column is a group of nine cells setup vertically
 A block is a group of nine cells setup in a 3x3 square,
and the puzzle has nine of these squares.

These few rules should help you solve your first puzzles. Have a nice time playing sudokus!