If you have Keynote installed on your computer, you can usually import a whole slide presentation in one go from the Import Button → Import Slides. The files can either be Keynote or PowerPoint files or PDF's.
If there aren’t enough sections, new sections will be created to allow one slide per section.
If you don't have Keynote or PowerPoint 2011 (or later), or for some other reason importing slides fails, it is simplest to save the slides to a PDF file, and then import the PDF file. Otherwise, ensure the Image Pane is visible and then copy one slide at a time from the slide sorter. You should be able to drag and drop into the image pane, but if that doesn’t work you can use copy and paste.
If you do end up using copy and paste, you can save time if you paste into the image pane with a single click by holding the Cmd key down as you click the mouse.
If you click near the top of a slide, that slide, and all the slides below it, will be darkened. This indicates that you can then drag them to a new position, either down or up. If up, you will overwrite any slides already there. The keyboard alternative to dragging with the mouse is to select a slide, then use CMD Up Arrow and CMD Down Arrow to move that slide, and all the slides below it, up and down.
You can use the usual Cut, Copy and Paste to move images around. These are available on the context (right-click) menu or with the usual shortcuts, CMD+x (cut), CMD+c (copy) and CMD+v (paste).
You can drag and drop images. If you drop onto an empty section then the image will be moved. If you drop onto a section that already has an image then the two images will swap positions.
You can right-click on a slide and choose 'Extract Slide Text' to copy the text into the Text Pane or Reference Pane. If you wish to extract the text from all the slides in the project, click 'Extract text: all slides' from the Images side panel. See Extract Text for more information.