There’s quite a bit of mains hum on that , which can be removed with Steve’s obviously titled plugin …
Then apply Audacity’s native Noise reduction to reduce the hiss ( don’t over do it: too much makes it sound computery).
Then squelch the hiss at the start (and no-doubt end) of the track down to near flat-line silence with a noise-gate , e.g. another plugin courtesy of Steve …
