Go to your Nearpod Library and select a lesson and choose edit. Select add slide.
Select add activity, go to the right and select Memory Test.
To search for images in the web, use keywords on the left bar. You can also look for images by browsing your files, your dropbox or your box. Then, just drag and drop them onto the boxes on the grid. They will automatically duplicate.
Once you're finished, hit "Done" on the bottom-right corner. It might take a few seconds to save. Then hit "Save & Exit" on the bottom-right coner. And voila! You're done.