Ok so I am trying to do this bathroom project myself. I have bought a new flange and tailpiece set, and took my old p trap to Lowes to have the plumber guy match up the right parts for me to purchase. I have attached everything together and I am getting leaking around where the new p trap and old goose neck (or pipe sticking out of the wall)connect. It's where the nuts connect. It's a constant leak. I have tried tightening, used Teflon tape, etc.

Before I noticed this leak, I as having leaking from the flange area. I noticed when I put plumbers under the flange and connect the tail piece underneath, I have a really hard time connecting. It's like my sink it really deep or something. I keep having to undo the flange from the tailpipe and redo everything if I move the tailpiece too much while working under there.

I really needs some help. Thank you so much

There are 3 basic pipe pieces under the sink. The tailpiece(vertical pipe attached the flange), the trap (U shaped pipe) and the trap arm(L shaped pipe between trap and wall piping). If the leak is from the connection of the trap arm to the wall piping, do you have a gasket slid over the trap arm, under the nut? The trap to trap arm connection might require a gasket(sometimes the trap arm has a rounded ball end that seats directly against a taper in the trap end) and the tailpiece to trap connection requires a gasket.

The seals are the plastic rings that came with the trap. If you look closely at them, they are tapered. You slide the nut onto the pipe, then the ring, with the smallest part of the taper, away from the nut. When you tighten the nut, it pushes that tapered ring into the space between the pipes and seals it.