Every application and window you open will have a help tab in the menu on the top left of the screen.
The iMac
There is no apple key on a newer iMac.
The iMac is an Apple computer.
This seems to be more of a technical problem. You should take your iMac into the nearest Apple Authorised Service Centre for help.
The Apple iMac is a computer and its purpose is to compute.
One can read Apple iMac reviews online at various websites. One can read Apple iMac reviews online at websites such as CNET, TechRadar, and Computerworld.
You do not make the iMac, Apple does.
On an iMac you can go to the System Preferences under the Apple Menu, then go to NETWORK. Choose which device connects you to the internet, wether it be wireless or wired, then click ADVANCED. From there your 'DNS' tab is clickable and will give you the specified information.
I do not have a 24" iMac. I have a 20" iMac. Apple no longer sells the 24" iMac. If you will click the Apple logo on the top left of your screen and then click About This Mac then More Info you can find the answer.
the iMac
Apple
Apple