Keyring Frontend examples to start from

If you mean “front end” as in “not in wp-admin”, then Keyring is not really written for that scenario. It can probably be made to happen, but that’s not really where it was intended to be used.

For a bunch of examples of using it to connect to/download data from, see https://www.ads-software.com/plugins/keyring-social-importers/

If you’re looking to post, then there’s going to be a bunch of set up/connecting etc to do before you get to the point of actually posting (most of which could be similar to what you see in the Keyring Importers linked above). Once you’ve got all of that, you’d use the request() method which is inherited by all of the services:

$service->request( $url, $args );

At some point I’ll try to get a tutorial online for how to do certain things, but for now the best way is to look at the code.

Good to know!
Thanks for the tips, and yes, the social importers has excellently commented code to follow. Of course, tutorials will be always appreciated.
regards,
Andrea