VW Polo - Coolant level too low - Clio87

Hi,

Re VW Polo - 04 reg

I've just filled up engine oil and noticed that the plastic bottle with the coolant in it is about 1cm below the MINIMUM level. I have a few hundred miles to drive over the next few days. I've never had to fill coolant up before and don't know how to do it - am I safe to drive for the next few days and then get it into a garage?

Or is it easy to do? I don't have any coolant but I googled and some people said you can just top up with ordinary water and then get the correct level of/mix of coolant put in afterwards. Would this be okay?

Is there a cap somewhere on the top of the bottle that just unscrews to fill the water into?

Sorry to sound dim and I haven't looked at the manual yet - just saw it was low and am panicking!

Many thx for any advice.