Actually, I'm not sure these two parts cover the whole story; there is no mention in post if more is coming & I've'nt heard the audio. But I've read the text version of the story, also online. Among the better first contact stories by anyone.
This story is a variation on the premise of Leinster's much better known "First Contact", the story after which this subgenre is named & without which no first contact anthology is considered complete. Audio of "First Contact" is online, but I'm not aware of any online copy of its text.
Related: Stories of Murray Leinster.