First you need to understand that while the lock icon of the layer you can’t change it, edit or change in any way, so we need to remove it or make a new layer similar to the background.
To do this, go to the desired layer and click on it 2 times with the mouse – in this case, the lock icon will disappear and we will get the layer that can be changed. When this occurs, a dialog box with settings for the new layer – here you can specify the layer name, color and blend mode with an opacity value.
There are a number of actions that will help us unlock the layer. Go to menu Photoshop Layer-New-Layer from Background. By doing this, we create a new layer out of our background.
Oh, and finally, the most simple action – press CTRL + J, or duplicate the layer. But in this case, you will either have to remove the visibility of the bottom layer (background default), or to delete it.
The most effective method is to press 2 times the mouse on the background, but if you back the plan will be required in the future, I recommend that you use the duplicate layer.