Learn to field strip your AR. This is something you need to know how to do if you are an AR owner whether you shoot a little or a lot.
It will be described in the manual if you have one, and a thousand times over on the internet, in text and video.
This one is very informative and will take you through taking one down as far as you will need to go and putting it back together.
https://www.youtube.com/watch?v=1ET1MiCm-0E