The rosin paper is not a bad idea but it needs to be glue down with a good multi-purpose adhesive. Then glue the one foot squares down with the same glue. A 3/32 to 1/8 inch notch trowel should be used. When you lay out the room, measure it in both direction. the object is to get the same size cut on both sides. Say it is 12ft 3inches wide. That would make an 1 1/2 cut which isn't good. Add the three to twelve to get fifteen and divide that in half, that makes a 7 1/2 cut. Do the same in the other direction and chalk two reference lines to start the tile against.