Once you have followed the installation instructions (see Installation Procedure), loading Sheeple into a Lisp image is as simple as:
(asdf:oos 'asdf:load-op 'sheeple)
(in-package :sheeple-user)
Sheeple should work on most Lisp implementations that support weak tables with key weakness, although it's mainly written and tested in SBCL and Clozure CL on Linux x86(-64).
Sheeple also includes a suite of tests you can run on whatever platform you're trying to get it to work on. The test suite depends on Fiveam. To run it:
(asdf:oos 'asdf:test-op 'sheeple)
And watch the tests scroll by. All tests should pass as long as you're using a tagged release.