Hi Keith,
of course there are as many ways as there are members on this forum.

The way my wife and I started, was at a friends party. And yes I played everything from sheet music. Except one song, nothing was memorized. Big deal. Nobody noticed/cared. We did a couple of other parties, then we found enough courage to ask for a gig at a local piano bar, where we used to hang out.
Think about the way that makes you most comfortable, so you can get the hang of it.
Don't worry about the sheet music, as long as you are playing with your heart, people will respond to it.

The main thing is that you have fun, no matter what you do. Especially in the beginning, for positive encouragement and reinforcement.
Hope this helps a little.
Eric