There are so many things that are just not explained and even when stopping the video and going back to check, there are things that are not explained. I have to assume things, so this is not a course. This is a demonstration video.
My mirror is like 10 years away from where it should be. 
At some point we have to extrude this part of the car but mine just extrudes the lines not the entire face. 
then when I fill those up with ctrl + F as mentioned in the video earlier. and I try to move them like in the video, this happens.
so no sorry this is not a beginners course if things are not clear from the get go.
Hello Enma. Can you point us to the time stamps where things are left unexplained? We can help you out and clear things up for you, so you don't get stuck. Chunck is known for being the teacher that explains every little thing and takes his time explaining concepts, first time we've seen this feedback for one of his courses.
Perhaps you're opening Blender for the first time. If so you can head to the Basics and Fundamentals, because in these courses where you're building up to an end result, usually there's things that are too basic and teachers assume you're familiar with them to speed things along. Just in case, leaving you some links.
Blender Basics: https://cgcookie.com/courses/blender-basics-an-introduction-to-blender-3d-4-5-lts
Fundamentals: https://cgcookie.com/p/core
Ok I see, yeah seems like you need to watch the Fundamentals first. There's Basics for concepts, Fundamentals build some foundations and then you go to Beginners Tutorials where you start to focus on building stuff, but you need a grip of the basics or what mostly happens is that we tend to get frustrated because we feel nothing works.
I'll leave you an extra link for the course where Paul breaks down all the modifiers, for when you want to hear a specific one broken down:
https://cgcookie.com/courses/course-modify-a-complete-guide-on-blender-s-modifiers-84c3c6a66db79804
The mirror works with the object origin, but Chunck probably doesn't go through the basics of it, or each time people use something on a course and has to explain it all over again, courses would be 300 hours long all the time. There's lots and lots of prerequisites in Blender, little things that of you don't know, things gets wonky fast.