How to add extensions to Gemini

I was driving home the other day and wanted to call my partner and let him know that I was stuck in traffic. (Not an unusual event on Brooklyn’s Belt Parkway.) I’ve got a relatively old car (it’s a 2007 model, so we’re talking no real smarts), and so I depend on my phone rather than any built-in intelligence to deal with calls, music, etc. Usually, there’s no problem, but this time, when I called out, “Hey Google — call Jim on his mobile!” my phone informed me — in a very…