Due to TLS security issues with older versions, the plugin requires QGIS3 or above.
The Socrata plugin is added the 'Web' menu.
Enter in the domain. Username and Password are optional fields.
You can use the "Get Maps" button to get a list of all map assets on the domain or conversely enter in the dataset ID if you have it.
By clicking OK the map will then be added to your project.
All maps on Socrata are in WGS84 and are retrieved through the GeoJSON endpoint.