Testing angular forms

I am trying to test an angular app in protrator and I do not understand something. I put this line there

beforeEach(function() {
    browser.get('http://juliemr.github.io/protractor-demo/');
  });

And I want to refenrence the elements of an HTML form using this line:

fdescribe('Protractor Demo App', function() {

  var goButton = element(by.id('gobutton'));
  
  ...and test its result

In protractor we do not put the test files corresponding to a specific .ts file in its folder, so this test searches in the whole project for an id gobutton or it searches for an id gobutton that belongs specifically to the link that I have put on browser.get()??

And my next question is if the page I wanna test requires a login, can I just use browser.get url of this page and test the elements or I should do the part of logging during my test?

And is it normal if my browser closes itself afterexecuting one test, or it should stay opened?