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
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.
Filters > Lights and Shadows > Drop Shadow, etc.
go to file> open> then select the picture you want.
You have to use the same layer to dodge or burn. It won't work if you use it on a new layer.
To superimpose pictures in GIMP, open both images in separate layers, adjust the opacity of the top layer to see both images, and use the Move Tool to position and align them as desired.
Actuall you don't add fonts to GIMP but you can add fonts to your computer to be used on GIMP.So download a font from a site like: Dafont.com Then Download the font to Computer>Local Disc>Windows>Fonts Then Next time you open GIMP you should have the fonts the Typing button. Hope that helps