Note, that your text will automatically be placed into a new layer (cf. pic 06). Layers are most important for such kind of tasks, because you can place elements in the photo without destroying any content behind the elements -- in our case the text. So it's quite easy to experiment a little bit and move elements/items/text around before you find their final position.
Note, that the layer information is only saved when you save the file in GIMP Format (.xcf) or Photoshop Format (.psd). JPG (or GIF, PNG, etc.) does not support layers, so just make sure you save your masterpiece in XCF Format before you save it also in JPG for publication.