copying formula to entire row with fixed cell reference

I always have had difficulty in copying formula to many cells or for every cell in a row with fixed cell reference in that forumla,


for example:

I have formula in cell B3 as = B1+C3
so when i copy cell B3 and paste it in B4 the forumla will become B2+C4
but I want the B1 cell to be the same in every formula (fixed cell reference)


until today I use to edit it manually, (lazy to spent few min to read)

But it is very simple

I just have to use $ for the row and column identity that should stay fixed



now if I copy B3 to B4, the formula of B4 will be