Hello ! Here i am again

I want to write in a Word document starting from bookmark index.
From now i was working in a empty word document so i wrote into the first paragraph.

Today (working in final document) i want to get the index paragraph corresponding to my bookmark starting index.
I already get the bookmark index and know how to write from specified paragraph index.
I don't know how to link both.
Any help will be apreciated !

BR,
Vincent