Unable to use external mic on a Inspiron 15 7k

Hello. I've been having an issue with my mic while having my laptop and my current situation is that I'm using Astro A10 which has a built-in-mic. I'm having struggles with setting up the mic after recently learning that I was using the laptops internal mic. I'm sort of going everywhere with this

Overall I just don't know how to switch from the internal mic to the external mic (again I'm using Astro A10 which has a built-in-mic). If anyone has a solution I will try anything you have to get this fixed.