1)You have to keep it at room temp and not in fridge.
2)After few days, the fondant may get a little dry, add little more water, oil and icing sugar and give a good knead to make it soft again.
3)When working with fondant, cover the remaining unused fondant in plastic wrap and store in air tight container covered or it will dry up.
4)if you want to add colours to fondant, take a little fondant and add some colour and knead well. Add more icing sugar if needed.