Dashboard/admin nav bar

Up until now I have been using pre-made themes on my sites.
I decided to go out on a limb and make my own theme and i’m coming along pretty well.
I have ran into one small problem though, my new theme works and all however the dashboard/administration bar that usually appears at the top of the website when you are logged in, I can’t get it to show up?

I’m assuming there is some kind of code I need to add to my header file?
Can anybody help?