Not easy....usually contact cement on both sides

Thanks for the response. Both sides meaning the concrete and the back of the carpet? Would it help to acid etch the concrete? Also how do you think it would work to mount a tack strip on the top of the wall by the ceiling?

Please consult the products installation instructions or the manufacturers techical [installation] services department for precise information on verticle surface application.

That said, if you install the carpet with contact adhesive you will probably void the warrenty, as I have never seen contact adhesive recommended.

We would use a recommended multi-purpose adhesive applied with recommended trowel notching, and roll completely with a hand roller to ensure recommended adhesive transfer.

As to prep, just like on the floor, scrape/grind/stone the high spots and fill in the low spots with patching compound mixed on the thick side to ensure a smooth surfance that wont telegraph through.

Glued carpet on verticle surfaces is very messy and a pain in the posterior even for the consumate professional, so make sure to protect your other installation area surfaces, like the floor below the area you wish to cover, etc.