As I tried to show with my answer on SSE (before your question there was deleted), you probably want to go through the walkthrough video to understand which instances are being referred to:
Essentially, you will have two applications that are connected. One is your Sitecore Experience Platform instance that you have installed, and where the plugin you downloaded needs to be installed. I believe you have that side figured out.
The other is your Content Hub instance that you have received from the Stylelabs team. This is a SaaS environment where you put all your DAM content, and are possibly doing content workflow.
Once you have both pieces, the plugin is asking for you to configure the URL to your Stylelabs instance, so that Sitecore platform knows which Content Hub to talk to.