Changing oil and coolant

So instead of paying someone to do this I've decided I want to do it myself as I am doing most other jobs myself.

Problem is, I've never done either of these before so am a bit worried about what might go wrong.

Changing oil doesn't sound so bad, drain oil, refill with 4.5 litres. Change oil filter element. (will double check capacity though)

How on earth do I go about doing coolant? I think I found a drain tap the other day but I've heard stories about heater matrixes and air locks so I'm getting a bit worried. Is it a case of draining, then refilling from the coolant expansion bottle as others suggest?

Edited 4 December, 201312 yr by yesiamtom