With Gimp you don't have to create a new layer for text because the text tool creates a new layer for you.
- Select the text tool.
- Choose font type, text color and text size.
- Move it using the Move Tool (The icon with 4 directional arrows)
- Make sure the text layer is the active later and be sure to choose "Move Active Layer" option under the Move Tool options. This way you will only move the text layer and nothing else.
- Set the opacity to the text layer to about 50 or so.
- You can find the opacity selector on the layers tab or window just above the "Lock" option.
It's optional but you can also use the Rotate for a diagonal look or Transform tool for a perspective look.
I hope that helps.