Im about to do my first oil change on My EB V8, and i need to know how many liters of oil will i need and what would be a good oil.

I have noticed from time to time on a cold start its gets a bit tappet noise
for a few seconds, is that the oil thin or thick.

I have heard of people change the oil and it became noisey after the change

First of all you'll need 5 litres of oil.

Second, noise on start-up is generally oil too thick. Ford reccomends a 15w50 but i was running a 15w40, anything around 10w40 to 15w50 will be fine.
I have been using Nulon lately and have been very happy with it, but before that it has always been penrite HPR15.