looks like you got it right!
you might want to unplug or put a valve on that air line so it doesn't make so many bubbles ... they make noise and are bad for plants
the extra part is a lift-tube adapter, so if you were using the filter with an under gravel system, it could connect to one of the tubes coming up
if the flow is too strong for your tastes (the fish probably don't mind much), you can websearch and see if they make a "spray bar" for your model filter ... or depending on what size pipe that outlet is, you might be able to just use some pvc
pipe and some fittings (check out the gray plastic pipe that is sold as electrical conduit)