Put it in a box on the particular slide. If you plan to talk them thru it, just start with the cover then say
"Ok, I'd like to walk you thru my portfolio - if you'll just open it up the pdf we'll start on page 1. Please let me know if you have any questions. You got the pdf open? Great! *start talking*"
You don't have to control the 'playback' of what they are seeing. Just tell them when you're going to a new page.
Make a FaceTime call and share your screen with the presentation open in full screen. Did that multiple times for clients around the world. It's also possible with other apps, just google the name of the app + "share screen".