The sbvPlugin can be installed simply by issuing cabal install:

     cabal install sbvPlugin

This will also install the SBV library if you do not already have it.
You should also install an SMT solver, preferably the default solver
used by SBV; i.e., Z3 from Microsoft: <http://github.com/Z3Prover/z3>.
Please make sure that the "z3" executable is in your path.