Assuming monero-wallet-rpc is running on port 18082 and requires authentication.
Get wallet:
curl -u <user>:<password> --digest http://localhost:18082/json_rpc -d '{"jsonrpc":"2.0","id":"0","mehod":"get_balance","params":{"all_accounts":true}}' -H 'Content-Type: application/json'
You must pass –digest for the auth to work.
Rest of the examples can be found at https://www.getmonero.org/resources/developer-guides/wallet-rpc.html