2-D Linear extrusion coupling with 1-D

Hi!

I have been trying to use a variable of 2-D component in 1-D component. I am trying linear extrusion coupling. Please can someone give the steps(i.e which and how many vertices should I map).

The variable in 2-D component has the same value across a boundary. I want to use that value in 1-D geometry.

Thanks in advance!