If you just graduated college or have no network, you can reach out to alumni and mention that connection. Or, you can ask personal friends/family for contacts (will probably be local companies, which may be a first step job).

Or you can reach out over social media. "Hi there, I follow you on X and am just getting started in the industry. Do you mind if I ask a few research questions?" A friend of mine just used this technique to land a role in an industry where he had no contacts.

If the situation is "good luck getting through to people on the phone", then that probably means this person is not a real friend of yours, they are a stranger, and you shouldn't try. You should be reaching out to people who actually know your name, or you have a mutual friend.

Reaching out to alumni works in some cultures, but in much of the world they will universally ignore you.