How can I add a second tag name to an image? PSE 2018

I cannot reconstruct how I was able to name tag an image with a person's name.  I simply stumbled on a screen that allowed me to do that, but I cannot remember how it was done. Therefore I need baby step by baby step instructions for that.  And then I need the same baby step instruction for adding a name tag to an image that has more than one person.  I have never used Organizer before.  Perhaps if I had a User Guide in PDF, would be searchable on key words, I would try to look it up.  The HTML guide takes me in circles and never yields strictly on-point instructions that solve my problem