You open up the pic and then click the layer button and then click add layer and the layer box will come up.
Press control + L to open the Layers window.
Click on windows / dockable dialogs / layers channels paths
In the "Layers, Channels, etc" window, right click on a layer and click delete.
There's a specific command for that under 'layers'. You can also do it in the layers "toolbox" (wrong term- but the stuff on the right side of the screen)
Press Control + L to re-open the Layers window
To navigate different layers in GIMP, open the Layers panel by going to Windows > Dockable Dialogs > Layers. You can select, hide, or delete layers by clicking on them in the panel. Use the eye icon to toggle visibility, and drag layers to rearrange their order. To adjust a layer's properties, right-click on the layer for additional options like opacity and blending modes.
IF your picture has multiple layers (it may not - jpeg's don't when brought in) it will allow you to determine which layer is being modified by the editor, and to rearrange which layers are on top.
In GIMP, to draw on multiple layers simultaneously, you can use the "Paint on All Layers" option. First, select the layer you want to draw on, then go to the "Tool Options" for your brush or pencil tool and check the "Paint on All Layers" box. This allows you to apply your strokes to all visible layers at once. Remember to ensure that the layers you want to affect are visible and not locked.
In GIMP, there is no strict limit on the number of layers you can have in a single project, but the practical limit is determined by your computer's hardware and memory capacity. Each layer consumes system resources, so performance may degrade with a very high number of layers. Generally, most users find that they can comfortably work with dozens to hundreds of layers, depending on the complexity of the images and the capabilities of their system.
You have to use the same layer to dodge or burn. It won't work if you use it on a new layer.
Filters > Lights and Shadows > Drop Shadow, etc.
go to file> open> then select the picture you want.