Krsna is the Supreme Personality of Godhead and cause of all causes.

This includes being the original cause of all Narayana/Visnu expansions from Goloka-Vrindavana, who set up perpetual unlimited Vaikuntha planets surrounding Goloka-Vrindavana, together taking up 75% of the Spiritual Sky. 

The other 25% is the temporary (decomposing) material worlds.

Krsna is therefore the original source of Maha-Visnu who creates the material universes called Brahmandas that originate from His breathing and the pores of His skin as seen in photo below.

Furthermore, deep inside each Brahmanda material universe, there is a "secondary inner" enclosed universe where Maha-Visnu expands as Garbhodakashayi Visnu, from whom Lord Brahma appears and builds the many planetary systems in his material universe. 

There are unlimited Brahmanda universes, each having a secondary universe inside of them meaning each has their own Garbhodakashayi Visnu and Lord Brahma.

In these "secondary material universes" created by Garbhodakashayi Visnu within each Brahmanda universe, Lord Brahma builds the planetary systems, in our universe there are 14 planetary systems.

In other material universes inside their Brahmanda, they have many more planetary systems than just 14.

Our secondary universe is one of the smallest.

The size of each Brahmanda and inner universe depends on how many heads Lord Brahma has, in our material universe he has four heads, while in other material universes Brahma may have 10, 20, 50, 100, 100,000, one million or 10 million. The workings of this material universe is beyond our comprehension.

There is only one Maha-Visnu but there are a unlimited number of Garbhodakashayi Visnus, Lord Brahmas and demigods (administrators within each material universe who are in charge of a particular field like ministers portfolios in the Government).*.