I'm a bit confused with the sump plug for my 206cc 1.6L Petrol (1.6 L TU5JP4 I4). I can see underneath there is a big flat head hex bolt, it looks approx 25mm. I was looking the exact size online so I can buy the correct socket and I can see in most of the images shown, a hex bolt with an Allen hole also. Is the sump plug located underneath the sump (and what size is it)?

My second question is: Where can I find some instruction about how to remove the oil filter. It looks too crowdy in there and I was wondering what is the easiest way to remove it and replace it.