am looking for a quick way to background-color every second row
grey.

So for if example I have used rows 3-76, I want to background colour
every 2nd rows 4,6,8,10,12,14,16,18,20,22,24,26,28,30...76

Right now I need to left click and hold ctl button to manually
highlight them all, then click on the grey background color fill
tool.
But maybe there is an easier method!

Thanks