Two main things you'll want to do with a slide, once you've found the one you want, are to copy it to a presentation or edit it, in case its content needs to be changed. There are several ways to copy or to edit. You can open the slide in a larger window, as you saw before, and find both editing and copying commands. Or you can work from the main library window. Click Play to get an idea.
Note The second course in this series, SharePoint slide libraries II: Use slides in the library, goes through each step for copying and editing slides and for updating a presentation with the latest version of a slide from the library.
Tip A library includes many options that help you use and customize it. For thorough demonstrations of how to rename slide files, create folders and rearrange slides, delete slides, and do many other things, see the course called SharePoint document libraries IV: Tips and tricks.