yang the Bosch Laser GLM 50 C has a function to divide a length in equal lengths and shows it in the Display. Usually you measure the length of the room and divide it by the width of the Board. Then you see how much full Boards you get and the rest. This Rest shows you how you have to start. Because you want the First and the last Board to be equal sized.
For example your room ist 6,3 meters. Your Board is 192 mm
So 6300 mm divided by 192mm is 32,81
So you get 32 boards and 0,81 rest
0,81 x 192 = 155,5
That' s the last Board.
For equal size you take 155,5 + 192 = 347,5
347,5 : 2 = 173,7
That' s your first and last board equal sized