Now 5 years ago i could have done this with my eyes closed but after all my treatment i cant remember shit about excel so im hoping you guys can help out?

Main workbook only has a few sheets and has three boxes to enter details, which then need to be added to a different sheet and on a new line each time.
she has created a new macro called add which copies three boxes of information and pastes them into the prices page as we need it to but then we have hit a wall.
This is the macro:
Code:
Sub Add()
'
' Add Macro
'

'
    Range("K24,N24,Q24").Select
    Range("Q24").Activate
    Selection.Copy
    Sheets("prices").Select
    ActiveSheet.Paste
    Sheets("add product page").Select
    Application.CutCopyMode = False
    ActiveCell.FormulaR1C1 = ""
    Range("N24").Select
    ActiveCell.FormulaR1C1 = ""
    Range("K24").Select
    ActiveCell.FormulaR1C1 = ""
    Range("H24").Select
    
End Sub

She is supposed to add this line of text to the macro called add :
Code:
  Selection.End(xlDown).Select
Cells(Selection.Row + 1, Selection.Column).Select
This is supposed to add the copied text in the macro to the next free row on the product page, so its not overwriting the previous entry.

we paste that in and always get an error?
I have added the main workbook called model.zip
Please anyone can you help this needs to be handed in tomorrow!
model .zip

PLEASE HELP!!!!