You weren’t. All you could do is figure out what’s different from Excel and then practice in Excel but following the ‘Pearson rules’ of the spreadsheet. I created an Excel file for each of the last 10 years of exams and practiced all the historical problems like usual, but in Excel instead.
So far, I’ve spoken to at least 15 people who lost time (between 15 and 20 mins) for one reason or the other (mostly technical issues). I wonder how they’ll adjust for that. The irony is that, it may be easier to pass with an adjustment (if you lost time) than if you had no adjustment and left a few questions blank.