I cannot run the JavaScript debugger by pressing "ctrl+J" combination of keys.

WHat is "recent files list"? Is it button "Home" or something else? WHere do I find it?

The key thing is that you need to know the difference between Acrobat (paid for) and Reader (free). Also the difference between Acrobat Pro and Acrobat Standard. Trying to follow instructions written for the wrong one will generally cause pain. Also disappointment; most things have to be paid for.

For some older versions of Acrobat Reader one needed to edit Window's Registry to enable it.

If you want to add a menu option to the "View" menu item one can use the following code:

app.addMenuItem({cName:"Console Window", cParent:"View", cExec:"console.show()"});

If you want more see PDFScripting.com Free Acrobat Automation Tools

If you are using any version of Adobe Reader or Acrobat Reader, the JavaScript console is not readily available to you. Not even to show an error.

With Reader one can set JavaScript errors to open the console by editing the programs " Edit =>Preference => JavaScript", selecting "JavaScript, and then enabling the appropriate options.

If you want to add a tool or menu option then you need to add a folder level JavaScript file with the appropriate code.