If you're arriving by car in Jerez, beware that driving around is a bit of a nightmare - be prepared to get lost and do a few of those three point turns and u-turns!! Signs and directions aren't that great and there are quite a few one way streets and pedestrianised areas to confuse things further. In fact, just trying to get to the centre of town from the main highway is a trick in itself!
There are a couple of underground carparks near the centre, one underneath a plaza near the top of the pedestrianised main shopping street. If yuou make it that far, then just park and travel between the sights on foot.