Conditional Formatting of Cell Based on Another Cell

[MattBann75]

Hi,

I need some help 

I need to create some conditional formatting of a cell based on another cell.

I need to colour code the "Margin" where this is one of the conditions below - 

If the Branch is "SER" and the Margin is < 30% or if the Branch is NOT "Ser" and the Margin is < 40%.

Any ideas how to do this or, if it is even possible?

Thanks.