best approach to find your target audience on social media?

Read your competitors' reviews, the 3-star ones especially. People spell out who they are and what they actually wanted, in their own words. Good for targeting and you can lift the phrasing for your ads.

Do you have any customers yet? If you do, start there - who they are, how old roughly, what they do for work, which apps they actually use. That beats any guesswork. If you already post, the analytics on each platform show age, location and active hours of whoever follows you, which is often not who you assumed. No customers yet: look at two or three competitors and read who comments on their posts, not just the follower count. Hashtags and search inside the app show you the people already talking about your topic. Then just test - same post aimed at two different groups, and see which one reacts.