To Begin
Many people start solving a standard Rubik's Cube with the centers on each side. However, with a Ruben King cube, the centers have four different possible orientations because of the diagonal pieces in the middle. Begin by orienting a solid corner piece. For example, if the cube in the center is split orange and yellow, find the solid yellow corner piece and get it to the corner located diagonally from the yellow half of the center square. The yellow point of the split center should touch the bottom left corner of the solid yellow corner piece. Starting with a corner will give you the proper orientation for the side. The solid corner always points to the right angle of the same color center triangle.
Align Center Split
Once the solid corner is in place, so that you know the alignment of the square, then put the diagonal corners in place. Since you now know the correct alignment of the center piece, get the diagonally divided corner pieces in line with the center piece.
Duplicates
Each corner on a Ruben King cube has a duplicate corner that looks just the same but is actually aligned slightly differently. If you have a corner in place and simply can't get the rest of the cube to solve, you likely have the wrong duplicate corner in place. Look for the other corner that is nearly identical and move it into place.
Cross
Just like a normal three-by-three cube solve, once the center pieces are all aligned properly, make a cross on the side you want to solve, keeping the orientation of the center. It requires more concentration and attention to keep the orientation aligned as you are creating a cross.