If you have already solved the first layer, you can skip to Step 2.
Otherwise, hold your Rubik’s Cube with the yellow center piece facing up. Find the yellow & green piece and move it to the green side, the side that is green in the center.
Twist the green side 1 or 2 quarter-turns to move the yellow & green piece to the top. Your Rubik’s Cube should look like this:
If the two colors don’t match up, flip the yellow & green piece like this:
Solve the other 3 sides the same way so you have a yellow cross on top. You won’t mess it up if you use the bottom layer to move pieces around.
When you have a cross on top, you’re ready to solve the corners.