Need someones to add posts to Instagram.
is there any requirement for the people that want to join this task?
like minimum followers on our instagram
I think he is looking for someone to manage his Instagram account and create regular posts - like he said - 30 posts/week. That would be $15/week - a decent amount for a very under-developed country, but not even the pocket bucks for a USA kid for a month.

Depends on the actual work that he needs to be done. If you have to design quality posts then this gig is likely underpaid.