Both, Please toot an #introductions so we can get to know you 😀 add some hashtags too so we know what interests you.
You can find more people in the instance in the directory
(you can opt into this too once you have 10 "friends", and add tags to your profile) and the local timeline.
And this list of radio amateurs on mastodon, may be of interest: https://pad.dc7ia.eu/p/radio_amateurs_on_the_fediverse
And there are apps!
The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!