The best way to get an Invenio demo instance up and running immediately is by using Docker or Vagrant, for example:
$ docker-compose build
$ docker-compose up -d
$ docker-compose run --rm web ./scripts/populate-instance.sh
$ firefox http://127.0.0.1/records/1
This will start an Invenio demo instance containing several example records and all the needed services such as PostgreSQL, Elasticsearch, Redis, RabbitMQ.
For a detailed walk-through on how to set up your Invenio instance, please see our installation documentation.