I will try to help, but hopefully someone with more knowledge will hop on here soon.
to move a layer, such as the butterfly layer, you make sure that layer is selected in the layers menu. Then click on the move tool

, make sure you click the radio button for move active layer, then click the on the layer, and you can move it wherever you want. Ignore the little layer edge lines. To resize your butterfly, again make sure that layer is active, then click on the resize tool

and a dialog window will come up. click on the chain to link the length and width together if you want it to stay the same ratio. Then click on the butterfly and some lines with a center mark, edge lines, and corner marks show up. You can drag the edge and corner lines around to get the size you want. Then click ok or whatever on the dialog box (which sometimes gets hidden so first place it over where you can see a bit of it to click on to bring it back up front)
When all is as you want it, it's a good idea to go to each layer, and Menu>>>Layer>>>layer to image size. This makes all the layer edges line up with the original layer. And when you save a project in gimp, save as a gimp xcf file first, then I recommend saving as a png file. If you ever want to re-edit this file, you can open the xcf file and all the layers will be preserved. png is good to help prevent degradation of the image as happens with using a .jpg file