Of course the bearings etc are already greased – you didnt do anything wrong! Your hub is not broken its making the noise its supposed to…
However, by putting a slightly heavier coating of grease on the surface inside the outer shell where the pawls contact (you’ll see lots of notches) the noise can be made quieter. This involves you taking off the cassette and then dismantling the freehub shell into its component parts.
To be honest – I would leave it alone. It makes a clicky noise because it is designed to – thats how ratchets work. Some are louder than others – I’d just get used to it…