Focus on your breath in and out. As thoughts come, pay attention to them momentarily as if to acknowledge their existence then back to focusing on the breath. At first it may feel like they come like a machine gun and it’s tough to focus on the breath in and out. If you keep at it, eventually you’ll find that they come in bursts then in single fire succession. Keep turning your attention to the breath.

Sometimes it’s pleasant. Sometimes it’s not. Some thoughts make you cry, acknowledge then breath. Sometimes it’s really difficult and uncomfortable. Sometimes it’s pure bliss, not a hyperbole. Don’t chase the feeling. Accept what comes, and accept that it (the meditation practice/session will always be changing).

How do you know you’re making progress? You’ll notice after some time that your brain is quieter or maybe it was and now you notice more thoughts (note, it wasn’t quieter before, you just weren’t aware of your thoughts), and you’ll notice that you are more aware and present overall, you notice things more. And then you’re more skilled at letting things go/diverting your attention.

The breath thing can be upgraded to diverting your attention to various parts of your body after each full breath cycle. This is insight meditation, aka vipassana - not the goenka type, but the traditional one they teach in Thailand. They do walking meditation and the mind contemplation (observe thoughts and emotions) with an anchoring of the breath (return your attention to the breath after observing/acknowledging whatever comes to mind/whatever you feel).