How to experiment with different audiences?

So I know you're supposed to be very "user-centred" and basically hang out where your users hang out.

However, I want to experiment with a different audience...anyone have any tips on how to do that especially when it's different from our main user base?

For more context, I work with a cohort-based edtech startup (https://entrylevel.net/). We sell online courses to help people break into tech (Venture Capital, Product Management, Growth Marketing, UX Design, etc.). Students get a refund after completing the course (we make money through optional premium upgrades).

I want to experiment with more US and Canada audiences and our current users are primarily based in Nigeria and India. It's a bit difficult right now for me to reconcile these two very different groups and I'm not sure who to market to right now. Any tips appreciated!