Conditional formatting VBA multiple conditions - vba

Question

I am extremely new to VBA world and need some assistance with the VBA side of conditional formatting.
1) I need conditional formatting to be applied to column (M)
green under 7
yellow from 7-20
red greater than 20
With the overriding condition that if column (N) if it states NOPO, I do not want conditional formatting to be applied.
I have worked out a formula to use that indicates what colour is required but unable to turn that into VBA conditional formatting (this formula shows what colour and if the conditional formatting should be applied.
=IF(N2="osno",IF(M2<=7,"green",IF(M2<7,IF(M2>20,"red","less than 20"),IF(M2>20,IF(M2>20,"red","less than 20"),"yellow"))),"no format")
This is my current VBA script, as you can no doubt see it's very messy and was from a recorded script.
Sub Conditional()
'
' Notification_05 Macro
' Conditional Formatting
'
'
Sheets("Final").Select
Columns("M:M").Select
Selection.FormatConditions.Add Type:=xlCellValue, Operator:=xlLess, _
Formula1:="=8"
Selection.FormatConditions(Selection.FormatConditions.Count).SetFirstPriority
With Selection.FormatConditions(1).Interior
.PatternColorIndex = xlAutomatic
.Color = 5296274
.TintAndShade = 0
End With
Selection.FormatConditions(1).StopIfTrue = False
Selection.FormatConditions.Add Type:=xlCellValue, Operator:=xlBetween, _
Formula1:="=8", Formula2:="=20"
Selection.FormatConditions(Selection.FormatConditions.Count).SetFirstPriority
With Selection.FormatConditions(1).Interior
.PatternColorIndex = xlAutomatic
.Color = 49407
.TintAndShade = 0
End With
Selection.FormatConditions(1).StopIfTrue = False
Selection.FormatConditions.Add Type:=xlCellValue, Operator:=xlGreater, _
Formula1:="=20"
Selection.FormatConditions(Selection.FormatConditions.Count).SetFirstPriority
With Selection.FormatConditions(1).Interior
.PatternColorIndex = xlAutomatic
.Color = 470000
.TintAndShade = 0
ActiveWindow.SmallScroll Down:=-27
Range("M2").Select
With Range("M:M")
.FormatConditions.Add Type:=xlExpression, Formula1:= _
"=LEN(TRIM(M1))=0"
With .FormatConditions(.FormatConditions.Count)
.SetFirstPriority
End With
End With
End With
End Sub
Thanks,
Blake

Answer 1

A CF formula needs to return either true or false: you can't use a single formula to assign one of multiple colors, only to decide if a color should be applied or not. You will need three rules, each with a slightly different formula.
Sub Tester()
Dim rng As Range
Set rng = Selection
rng.FormatConditions.Delete 'clear any existing rules
AddRule rng, "=AND(M2=""osno"", N2<7)", vbGreen
AddRule rng, "=AND(M2=""osno"", N2>=7,N2<=20)", vbYellow
AddRule rng, "=AND(M2=""osno"", N2>20)", vbRed
End Sub
'utility sub: add a CF rule given the formula and a fill color
Sub AddRule(rng, sFormula, lColor)
With Selection.FormatConditions
With .Add(Type:=xlExpression, Formula1:=sFormula)
.Interior.Color = lColor
.StopIfTrue = True
End With
End With
End Sub