Hi @Adams,
SEMPv2 is the RESTful management API for the PubSub+ Event Broker and doesn’t offer a GUI of it’s own. It is available with a broker install so you can install a broker locally (such as using docker) if you want the service impl available locally.
And if you want a GUI tool that you can use to create/run your SEMP queries I usually recommend using Postman. They should have a linux installer and then you can import the SEMPv2 OpenAPI document into postman and it will generate you a collection to start with. This page shows how to do that.
Hope that helps!