Please use the following formula
=B2>=A2 for green (if the cell on the right is greater than or equal to the cell on the left)
=B2<A2 for red (if the cell on the right is less than the cell on the left)
Either the Apply to range or the formulas are wrong.
Instead of B:B use B2:B
Instead of B2>=A2 it should be B1>=A1
Instead of B2<A2 it should be B1>A1
Apply to range you might select the whole column B
Use a custom formula with relative references i.e. B1 instead or $B$1
How to conditional format in ...
Custom number formatting supports conditionals, but only two of them plus a default format. So, to display millions and billions of dollars, you can use Format > Number > More Formats > Custom number format with something like this:
[>999999999.999]$#.00,,, "B";[>999999.999]$#.00,, "M";$#,##0_M
Unfortunately, this will ...