It needs to be worn on stays. Since it is hooks and eyes closure, make sure your measurements when wearing stays are exactly the same or even a slighlty bit more - the tension will help keep the fastening closed.
Skirt is tied on with long tapes, so there can be a little leeway in the fit - best for waist size 30-35
The outfit is being sold at a discounted price as used, but is in a very good condition. What is more - it was used on the set of Horrible Histories - so a bit of a fame still clings to it ! ;-)