I was about to buy a slow cooker but my mum has given me a huge one she wasn't using. It's a bit old but hardly used. Now she said you have to put water underneath the ceramic pot but I've not heard this before. There are two grooves. Was this they way they used to work? Can't find any manual on line for this model. Anyone know?? Many thanks - am hopeless cook but really want to get going with better ways. X