It is quite easy to make a slide show with this program.
On the main page, click on Animated Gif. This page will display:
As you can see, it's now a simple matter of dragging pictures from your computer into the editing area:
Once you have selected the pictures to use, experiment with the options on the far right to get the effect you want.
In this example, I set the time to 1.5 seconds, decided the pictures should convert to a background color when they changed, selected a brown color for the background, set the pictures to fill the entire area, and chose small size.
When you are satisfied, save your GIF, then host it so that you can post it here. I've hosted it on Imgur, gotten the image code and pasted it here: