A simple guided tutorial, similar to the beginning of most mobile games, could help here. You literally walk the user through the process of adding one person (themself most likely) and then let them grow from there. With a 'skip' option of course, if they don't want or need their hand held.
"Where was I getting all this energy? I realized that what was draining me wasn't being social, it was being uncomfortable. It was the awkward situations, not social situations in general, that were sapping my energy."
Prior to that quote, you mention studying social skills. You also mention cutting old friends out of your life. Which path had a more drastic affect on you? Was it learning new social skills that made you realize you needed different friends, or did the desire for new friends force you to learn new social skills.
The social skills were key. Without them I wouldn't have recognized the negativity of my old friends or the positivity of my new friends. Before that I couldn't even recognize the bad state my friends were putting me in. Also, they enabled me to conciously make a good impression on my new friends.
I read How to Win Friends and Influence People, I read Introvert Advantage, both of which were informative. But mostly I watched a lot of videos by Lance Mason. He has a background as an engineer, so he was able to express social concepts in a way that made a lot of sense to me.
