you must move that A-M switch on your 18-55 mm lens in order to shift from Autofocus to manual focus. There is no other way around with the excellent 18-55mm lens.
This does not mean it is a bad lens. It is only ergonomically lacking instant manual focus override. Otherwise, this lens is sharp, sharp, sharp even at the corners. It is among Nikon's 10 best lenses ever! Read more about it here.
If you want instant manual focus override you should look for Nikkor lenses that have an "M/A-M" switch. This means, if your lens is in "M/A" mode, you can just turn the focus ring if you are not satisfied with autofocus. Example may include the excellent Nikkor 50mm f/1.8 G which I already own.
As for now, I must say, there's no problem with your 18-55mm. Just grab it and shoot!
And if you're not happy about its autofocus, turn on the live view, switch to "M" mode of the lens, zoom in the live view and focus until you get your focus sharp! That's done the trick for me for about a year. You can view one of my photos with the same camera and the same lens here