Exactly how is this accomplished and after I finish the project then what?
Could you elaborate a bit more on the project - Fair Isle/jacquard?, striping?, sweater panels to be seamed? Carrying yarn up the side is generally what it sounds like - the strand(s) not used in a particular row aren't broken, but are just picked up again when you get to a row where they are used. Assuming this is something to be seamed, the vertical "floats" end up right next to a seam on the non-public side of the piece, where they will tend to be unobtrusive.
"Hatred does not end by hatred; hatred ends by love. This is the eternal law." - Buddha