Currently changing the oil pump on my 4x4 Cossie, have brought a sump gasket set which included all the gaskets for the oil pump.

I have the gasket for the pick up pipe to the oil pump but there is also an O ring with this, can someone tell me where this should be fitted?

Also I don't have a gasket for the oil pump to cylinder block joint, should this be sealed with wet sealer or is it just a metal to metal contact?