I used to sell Pampered Chef - and own lots and lots of stoneware.
The first few times you use it, cook something with a bit of grease in it- grands biscuits work really well. Stones are porous and this helps season the stone, do it enough times and it takes on almost a non-stick surface.
do NOT use any kind of soap - this can result in a soapy taste to food cooked on the stone next time - just use hot water and scrape off any bits.
If after a few years the stone gets dark brown/black around the edges (perfectly normal) and you feel you must clean it, leave it in the oven and run a self cleaning cycle. This should not hurt the stone. Pampered Chef stoneware is fired at 2000 degrees, the self cleaning cycle is usually around 800-900 degrees, hot enough to burn off the oil residue, not enough to damage the stone.
A friend of mine called me to see if her husband had ordered a new stone from me - and didn't want to tell her he broke their pizza stone. Turns out he left it in the oven during a cleaning and it came out looking brand new.
I like stoneware for cookies - but don't like to put the cookie dough directly on the stone - I use parchement paper.