Hi Emilia,
Because the user interface runs in your browser, then information you are searching for can be found in your browser.
To see what is happening when you click a button:
* Open your browser's DevTools & go to the "Network" tab
* Login , go to that page.
* Enter text and click the button. On that "Network" tab in your DevTools you will see the REST API call(s) that are made when you click that button. You can click on those calls to see all the details that the UI sent to the REST API and how it responded.
To find the code behind the button:
* Right click on the button & select "Inspect" in your browser. This will bring you to the HTML code for that button
* In the parent HTML code, look for the *first* parent tag that stars with "ds-*", in this case it should be "ds-vocabulary-treeview"
* Search for "ds-vocabulary-treeview" (as a "selector") in the dspace-angular codebase. You'll find it in "vocabulary-treeview.component.ts"
* This means that the code behind that button is in that "vocabulary-treeview" component...specifically the "html" file and "ts" (typescript) file for that component.
Hopefully that helps give you some hints on how to debug this code!
Tim