If you received your spatial data fulfillment from Alteryx via mailed hard drive (as opposed to downloading) then you must install the data from that hard drive before it can be used. This is similar to the Guzzler and Allocate data installations if you are familiar with those.
You can install it on a local disk of your Alteryx Designer workstation (generally better for performance), or perform a network installation where you install it on a local network (convenient for multiple licensed users).
Once the data has been installed, when you place the Street Geocoder tool on the canvas, the dropdown at the top should list the data you've just installed.
