Kitchen sink leaky pipe

[bacchus]

Hi, I've been trying to fix a leak from under the kitchen sink. I replaced a number of components and fixed one leak from the trap, but now have another leak from the join to the waste pipe. See below (1).
I have 2 different types of pipe (2 & 3) and not sure how to connect them to a tight seal.
Many thanks for any advice.

 

[Knappers]

sorry but its hard to advise because this should be very simple and I'm unsure what the issue is.
There should be a rubber seal?

 

[king of pipes]

On pipe 1 there should be a plastic nut then orange ring and rubber seal this tightens onto the section marked 3