Welcome to ETO, umber!
What kind of details are you looking for?
If I were you, I would use a 555 timer instead. It's a lot simpler and easier to understand.
Der Strom
It is a supposed to be a rudimentary multivibrator based on an OpAmp used as a comparator. It has many errors in it that will prevent it from working.
Very poorly conceived by a rank amateur.