I signed up for an extra, shared gmail account for this. Very easy - one minor hiccup so I'll flag that here.
Assuming you are signed out of any gmail on your browser, go to gmail.com and sign up for a new account. There's some information you need to fill out (name, age, etc.) - I just picked the nickname my wife gave the car and my surname.
WRT the age, *do not* get cute (as I did) and put the actual age of the car or your purchase date. Pick an old date. Too young a date will cause you to have to go through many hoops to eliminate the cookies, etc because Google will not give addresses for humans under a certain age. I picked some random date in the 70s; worked fine.
At the entune site create a new account with your new gmail email address.
We are an android household so adding an extra gmail account was very easy - in the gmail app click in the top right corner (showing your account name) and, once in the new screen, add the car's gmail account you just created. You can toggle to that gmail account from that same top right corner of the app whenever necessary, and two people can be logged in at the same time, so no worries on that front.
I also downloaded the entune app and of course signed in as the car. It requires you use the email account to sign in, but see below for details on that.
It was not obvious to me (I was not paying attention when the car was purchased and apparently didn't read the right parts of the manuals), but you need to have a special account authorization to actually use the service - conveniently it comes with the car for free via the Safety Connect service for a period of 3 years. No idea what happens to the connectivity after that.
Call Toyota at 800.331.4331 and have your VIN ready to set up that service and get the acct.
NB - you will need to sign in to the entune app AFTER you have set up the full account or the EV mgmt apps will not show. Once you've logged in "post SafetyConnect" they should show up and work immediately.
The whole process took longer than I thought because of the need to establish the Safety Connect service, but was less than 20 minutes total, should be faster if following the directions listed here.