Stardates Explained - 20190923.1200

You don't understand the startdates?

Take, for example, 20190923.1200

Let me stick some spaces in some helpful places:

2019 09 23 . 12 00

That better?

20190923 means 23rd September 2019, and 1200 is in 24-hour clock format, IE 12:00 midday

Stardates in the Star Trek universe work in an entirely different way. Wikipedia has a good explanation on how Stardates work.

Events on this stardate