To try out Gramps Web on your local computer (Linux, Mac, or Windows) without interfering with your Gramps Desktop installation, you can use Docker with the following command:
docker run -p "5055:5000" -e TREE=new ghcr.io/gramps-project/grampsweb:latest
This will make a new, empty Gramps Web instance accessible at http://localhost:5055, where you can create an admin user and import a Gramps XML file.
Since this simple setup does not allow running long tasks in a separate process, importing a large Gramps XML file might fail due to a timeout in the first-run assistant.
To use media files from your computer you can mount the Gramps media folder into the container with
docker run -p "5055:5000" -e TREE=new \ -v /path/to/my/gramps_media_folder:/app/media \ ghcr.io/gramps-project/grampsweb:latest
Note that this will not persist the changes you make to the database when you restart the container. To properly set up Gramps Web, continue reading about Deployment.