Hi ahmedkl, well, it's quite hard to say without actually seeing what you're doing ( I guess TemurAmir was right about Skype being helpful in that sense!) so I'll try and give you a detailed description of the second layer (taken from your link). If you find a particular bit that you're having trouble with, point that out to me and it'll be easier for me or someone else to help.
(Assuming you made a white cross) Make sure you have the white face facing down, at the bottom of the cube.
Now, look for an edge piece on your top later (You would be very unlucky not to have even a single edge piece on your top row, but if you notice that they are all stuck in the second layer, I will explain how to deal with this further down). These pieces should be fairly easy to spot, as they will not have a yellow sticker on them.
Edge pieces have two stickers, look at the colour of the sticker facing towards you (ie,
not the sticker on the U face). What colour is it? Lets take the example of a blue-red edge with the blue sticker facing towards you and the red sticker on U face (shown on the left below).
Using U turns, rotate the edge until the sticker matches up with a centre of the same colour, as shown above.
It is very important that these sticker colours match! Notice in the image above, we have two examples of incorrectly positioned edges. The middle image is an easy mistake to make! Make sure that you line your edge piece up so that the sticker facing towards you is matching the centre,
not the sticker on U. In the image on the right, the green-red sticker is
not in the correct position to be inserted, and would have to be rotated so that it matches with the green centre instead.)
Now, look at the sticker on U face. What colour is it? In our example, it is red. This means our sticker wants to go in between the blue and red centre pieces, to the right.
To move the edge to that position, we perform the alg shown above. Don't worry about the brackets, I just put them there to help you see that pattern in the algorithm. At this stage, it's quite important for you to try and follow the edge and corner pieces as you perform this algorithm. This will help you understand what the algorithm is actually doing. You should notice that after you have performed ( U R U' R' ) the corner and edge are paired together. The ( U' F' U F ) part of the algorithm then returns them to the correct position.
Once the edge and corner are in the correct position, you can move on to the next edge. Look for another edge piece on the U layer, check the colour of the sticker facing you, match it up to the same colour centre, see which way you want the edge to go and then perform the appropriate algorithm.
You may come across a situation where you have no second layer edge pieces on the top layer. If this is the case, look for pieces stuck either in the incorrect position on the second layer, or possibly in the correct position, but incorrect orientation (as demonstrated below).
Once you have found these pieces hold the cube so that this piece is facing you, and either on the right or the left. (You can hold it in either, the choice is yours.)
Lets say you hold it so that the edge piece is on the right. If you were to perform the algorithm I gave you earlier, you could move one of the top layer edge pieces into the middle layer edge slot. This would then push the incorrectly placed middle layer edge out onto the top row, where you can deal with it as before.
Ok, that's about all there is to the middle layer. Post here if you have any issues!
