I want to now this too

Salaries at a startup can be problematic. Especially if you intend to raise funding at some point. If you have already raised funding, paying your salaries from that is bad form unless they are way, way under market. Having said that, VC's don't want their founders to starve, so you can pay a nominal salary but it should not be high. Your upside comes from company growth. Take a look at this article: https://www.brettjfox.com/how-do-you-determine-your-salary-as-a-startup-ceo/

Paying yourselfs salary is a bad idea at this stage. I don't advice co-founders to place themselves on a salary scale at an early stage, especially when there is no revenue yet.

Only you would know. What's a good salary in Nigeria in Naira?

Take as little as possible.

Nice problem to have. Assume you are killing it with revenues.