copying from 1 image to another

i am trying to copy from 1 image to another following a youtube tutorial.

in the tutorial

in the first image rectangular marquee tool then ctrl j then press v (move)

move over the title of the image to paste into in the top ribbon

move into the centre of this image and release.

in the tutorial when you move over the greyed out title of the  image i am modifying it activates showing that image on the screen and when you move into the centre of the image the new portion is pasted as a new layer.

when i move over the title of the image in the top ribbon it remains greyed out and does not activate

thanks

Dave