We've purchased Bruce wood flooring to install over vinyl over a concrete slab. First of all, do we have to rip up the vinyl. Secondly and most important, we want to install a sheet of the foam underlayment that's sold to soften walking on the area, but we're not sure where the foam goes. Does it go under the 1/4" plywood underlayment that we'll put down, or over it and under the wood flooring? Does it get glued, and if so does the wood flooring get glued to it? We assume we can't nail the wood flooring because it's over concrete which naturally doesn't supply a good nailing surface. Please explain exactly what we can do. Thanks!!!