So lets understand a day-night 24 hour period of Brahma (8 billion 640 million human years)

Lord Caitanya Mahaprabhu comes to this world every 8 billion 640 million years which is how long one 24 hour day and night of Lord Brahma takes to pass.

Further more Lord Caitanya Mahaprabhu only appears during the day-time between "sunrise and sunset" which is also when all the 1000 Maha-yugas take place.

There are no Maha yugas at night between "sunset and sunrise" of Brahma's 24 hour day.

A Maha yuga (Also known as a Catur yuga and Dvipa yuga) is cycle of 4 Yugas.

''Satya-yuga, Treta-yuga, Dvapara-yuga, Kali-yuga''.

Lord Caitanya comes at the beginning of just "one" Kali-yuga out of every thousand.

So lets understand a day-night 24 hour period of Lord Brahma

Every 24 hour day equals 2 Kalpas

1 - There is ''one kalpa'' for a "sunrise to sunset" day time that also has all the 1000 Maha-yugas in it.

2 - There is also ''one kalpa'' for "sunset to sunrise" night time period of Lord Brahma where NO Maha-yugas exist.

Presently we are in 28 Maha-yugas within the 7th Manu named ''Vaivasvata'' out of 14 Manu's that exist during Brahma's day-time only.

None exist during his night time.

There are 71 Maha-yugas within each of the 14 Manus.

This means Brahma's day has already gone through the first 7 Manu's plus the first 28 Maha-yugas of the 8 Manu we are in equalling 525 maha-yugas into Brahma's day.

This means it is about 11.40 am in Brahma's late morning period of the day

This further means the 1000 Maha-yugas in Brahma's day-time only occurs from "sunrise to sunset" or during the day-time that takes 4 billion 320 human years to pass.

During Brahma's night from sunset to sunrise, no Maha-yugas take place while Brahma sleeps and a partial annihilation takes place. This "sunset to sunrise" is also 4 billion 320 human years long.

One 24 hours full day of Brahma is 2 kalpas and takes 8 billion 640 million human years to pass through.

So presently as explained, we have already passed through the previous 6 Manvantaras in Brahma's day and are now into the 7th Manu out of 14 Manu.

All 14 Manus have 71 Maha-yugas in them.

And this is just one day of Lord Brahma only.

Brahma lives for 311 trillion 40 billion years then dies, then there is another 311 trillion 40 billion years of inactivity until another Brahma manifests.

All souls not qualified to go back to Godhead are stored in the Body of Maha Vishnu as individual units until the next creation of this single universe by the next Brahma.

There are millions of universes and Brahmas other than ours that are also deep inside a Brahmanda that all come from the body of Maha Vishnu.

Then they carry on and get another material body according to the combination of their karma and material desires from where they left off in the previous Brahma's creation in this universe inside our Brahmanda.