Conversation with the person you’re angry at if they’re available and willing to engage in good faith.
Otherwise you’re going to need an outlet like music, crying, video games, crying, outdoor meditation, crying, throwing a half full plastic water bottle at a metal dumpster until your worn out, crying, getting active in politics, or … Crying.
Seriously we get told we’re not allowed to cry and that’s bullshit. We have a built in stress response system. Go have a good cry and then think about long term solutions to whatever is making you angry. Someone is ignoring you? Disassociate from them. (Not from yourself, that way lies much therapy) Someone is violating your rights? Call the government. It’s the government doing it? Vote and protest.
Dealing with anger is always a multi step thing. The worst thing you can do is meditate and then nothing else. All you’ve done is escaped the moment. It will come back.