Hover over the slides you want to select in the grid view of your deck
Click on the empty square button that appears when you hover over the the top right corner of the slide
Select and deselect slides to your heart's content.
Making some changes
Once you've made your selection, you can rearrange your decks in the following way:
Media Frame - quickly give your media the same frame by clicking the Media Frame button
Power Layout - instantly change the layout of your slides using the Power Layout button
Media Position - shift all your media to the top, bottom, left, right, or background of your slides
Color - click the drop button on the top and select how you'd like to color your slides
Duplicate - make copies of your slides for use in the same deck
Copy to another deck - use this button to copy slides to another deck in your team
Delete slides - remove multiple slides easily using the red trash can button
Move the slide order - once you've selected the slides you want to move, drag one of the selected slides to the desired position. Paste® will stack the rest and move them all to that position for you.