best and worst outcomes

i have been attempting to forecast a balance sheet & P&L account for the
following year which i have managed to do, but am unable to work out the best
and worse possible outcomes and was wondering if anyone knew how to do this?

thanks

If you know the values you want to use for best and worst cases, you could use Scenario Manager (Tools > Scenarios). I'd like to suggest that you first create a "Normal" scenario, that keeps your current values. That way, if you accidentaly close the sheet in the middle of one of your other scenarios, you can still retrieve your initial values.