finally ,some senseoh are you DEFINITELY sure of this

I think I should definitely be sure, since I am speaking this language now for 23 years 

Here is a native that wants to help you

It is mostly used when one thing is happening after another. However in this case you also use "and " in English, not always "then"

e.g.: Kahvaltı yapıp evden çıktım. I had breakfast and left home. OR I had breakfast and then left home . (even if you don´t use"then", you know breakfast was the first action)

You can also understand that two things are not happening at the same time if you swtich the position of "-ip"

i.e.: Evden çıkıp kahvaltı yaptım. I left home and (then) had breakfast. (obviously I did not have my breakfast at home)

The thing confusing you is that we also sometimes use it for spontaneous actions!

Although "-erek, -arak" is more suitable in this situation, "-ip" is also used!

e.g.: Mısır yiyip film seyrettik. We watched a movie while eating popcorn./We watched a movie and ate popcorn.

OR

Mısır yiyerek film seyrettik.

 I wonder if the information above only depends on you having been speaking the language as a native for 23 years, or it is from books used in general education curriculum, reliable sources, linguistic articles and so? Can you cite some sources  supporting your point?