Excel multiple IF statement issue

[Anj12321]

Trying to amend the formula for the below

Columns - ABCDEFGHIJK

Date 01/06/2018

0	0	0	0	0	1	0	0
0	0	0	0	0	1	0	0
-4	-3	-2	-1	0	1	2	3
Jan-18	Feb-18	Mar-18	Apr-18	May-18	Jun-18	Jul-18	Aug-18

<colgroup><col span="8"></colgroup><tbody>
</tbody>

The date is 01/06/2018 so i have a formula with '1' showing in the top row which works fine in the June column. But the second row i want to show the 1 below the first row and then a '2' in the next cell (highlighted in red) and onwards with '3' in Aug and so on - i have used =IF(G2=0,0,IF(G2=1,1,IF(F2=1,F2+1,0))) but doesnt seem to work. Please can you assist, will very much appreciate it.

Thanks