Asynchronous tableView loading

Asynchronous tableView loading

So I have a class with methods that sends asynchronous requests to my
database and then returns the objects into an array, I use blocks as a
form of callbacks. I save the array in a singleton that can return it with
a method.
The problem is I have almost no experience with tableViews, and I followed
a tutorial that accesses data from an array and then creates tableView
cells based on the number of objects in the array, and populates each
cell's text label with the description of each object. Now I'm trying to
make it work with my method and singleton, however the tableView loads
before my singleton has recieved anything from the database, so how do I
get through this problem?