Finder Navigation using Arrow keys

Have you notice that in finder, if you want to go inside the folder you need to double click the folder or highlight the folder and press arrow right key. We cannot use enter to directly open the folder, just like in a PC. We just need some help of the Command Key.
To navigate in finder using just keyboard.

• You can use left or right arrow keys to view the content of the highlighted folder.
  
• We can combine Command Key and arrow keys to open the folder in the same window. But instead of right and left, we use arrow down and up keys.

To Summarize the equation:

1. To open a folder in finder or Disk Drive, Press Command Key + Arrow Down key.
2. To open back in previews window, Press Command Key + Arrow Up key.

Try it and you'll see..