how to analyse timestamp in ext4 manually?

how to analyse timestamp in ext4 manually?

I am doing a research on Ext4 and I believed I have understood the
fundamentals of Ext4.
I believe that you also know that Ext4 stores timestamp. In my assignment,
I have purposed to analyse the timestamp of Ext4 MANUALLY instead of
typing the command (e.g. # date -d @2220775699).
Is there a way to do so? I don't seems to find this..
In addition, why does the timestamp different from the timestamp in the
journaling?
Can anyone explain this to me? In simple words.
I will really appreciate it.
Thanks.
--Stupidgal--