how to solve a rubik's cube(1)

As you know this Rubik's cube is invented by Erno Rubik, a Hungarian Professor of Architecture and Design. it is launched in 1980. in a year this puzzle became the fastest selling puzzle the world has.
Do you know that there are some people who can solve this cube under 40 turns, even under 10 seconds!!! from any scrambled position?
and the craziest thing is: few people can even solve it BLINDFOLDED!!!
This cube is designed to challenge your mind and your imagination.
how to solve this cube?
here...



each face of a cube is represented by a letter:
F = front
B = back face
R = right face
L = left face
U = upper face
D = down face

code:
F = turn the front face once clockwise | Fi = turn the front face once anticlockwise
U = turn the upper face once clockwise | Ui = turn the upper face once anticlockwise
and so on...
got it? then ...
step no 1:
solve the upper green cross. ( actually can be any color to start with).
to solve the green cross, you have to solve each green edge piece on your own, one by one.

step no 2 :
solve the green corners.
find the corner piece in the bottom layer that belongs to the top(the green cross face on the top), then do the turns until that corner is on the front-right-bottom, then do this turns: Ri Di R D.
do this step for all the corners

step no 3 :
solve the middle layer edges.
turn the cube so green is on the bottom.
put red as front face.
you need to find the red-yellow edge piece, do U until the edge matched with the red face.then do this: U R Ui Ri Ui Fi U F
put yellow as front face, then repeat the process...for all the colors.
to be continued....