i need help with complex excel fomula

Job ID: 33458253

Budget: £10 – £15 GBP

I have a complex excel spreadsheet produced by someone who has now left the business
In 1 column of cells i need to alter the formula so that if a negative number is shown i need it to return 0 (and others cells will calculate based on it being 0). If the result is positive i need other cells to calculate based on the positive result