Dependency with timeline and duration

I’m trying to implement the simplest functionality - a dependency between tasks.
I have a timeline & duration and dependency column both ensure and adjust.
First of all, the dependency works only if you enter the dependency first and after that the duration. If you do it in different way it doesn’t work. Is this how it should be?
What this causes is that if I want to change the dependency after setting the duration, nothing will change.
Second problem - if I enter 2 dependencies, for some reason it only considers one dependency.
I would appreciate your help please.