To determine the coordinates for the final stage use the GRID, ROW, COLUMN formula below.
Inside there are banks of boxes lining the walls separated by black trim like a grid pattern.
The grid is upper left corner, rows are down, columns are over, this gives you a number.
N 28 12. [ (G621:R4:C6) + ( G351:R5:C4) + (G111:R3:C2) ]
W 082 43.0 [ (G401:R3:C4) - (G231:R5:C4) - (G171:R1:C4) ]