Oh, those buttons will later be "collapsed", if so desired, dropping their labels. They are intended to be "optional", you know.
You can load an image into the background as reference. In the file menu you can "Open..." Jpeg or PNG images. This then will open a preview window. You can then click at the bottom of the preview window the "Add to Drawing" button. The image then gets dropped onto your canvas.
Now you can "Transform" it. Once you activate "Transform", there is a guidance in the input tab as to how to proceed. I'm pretty excited about this feature, but it takes some getting used to.
The transform procedure has two phases. First you click & drag the image into position. Once you let go it turns into a rotate & scale function, based on the axis you now have to place. If you hold shift, as usual, it can lock direction, making it easy to scale the image without rotation.
However, the main idea behind this is to align images to an exact measurement reference. Most of the time these are scanned or photographed patterns. You should know the length of at least one of the lines on your image. This you can then align to a line you have already in your "drawing".
For that you simply make (or have) one line at the desired length and orientation drawn. Then, when you load your image, you grab the image by start of the known line in the image and drag/snap it to the start of your line in the drawing. Then, when you let go, you see that you now have an axis active that follows your mouse. Make this axis end at the end of your reference line in the image and then drag/snap that to the end of the line in your drawing. Voila!

It's a procedure that takes seconds and turns your image into a perfect reference to start tracing over.
