Looking at Jack's post item #24, are you calling the barbed part the one that is closes to the line? It's been a while but if memory serves me, you slip the barbed piece on the line, then an o ring. The middle piece I think is a hard plastic piece then another o ring. Slip the chrome outer piece back down the line, it's just a cover. Push the pipe,oil line, into the oil tank then push the barbed piece in place. It keeps the line attached to the tank.
I would look up in the tank hole first for rust, dirt, etc. and clean first. Put a little oil on the o rings first for easier instillation.
tourbox