[Support request] Bi-Value Cells, Promoting Numbers in Cell, Etc.

What is a “Bi-Value” cell? How is it created? Why is it important? Is a cell with 2 values in upper left hand corner a bi-value? If one number in cell is in upper left and one in upper right side bi-value? If both cell are in upper right hand bi-value? It seems that bi-value cells are important for creating chains and I am very confused as to what constitutes what is and is not a bi-value cell. Please help.

Promoting numbers in a cell: What is the criteria for promotion? How is a cell promoted? And what purpose does it serve? Please help.

Thank You