How does a newbie get started?
 

I never take taxis in my home town.

Rarely, I take them in NYC. Rarely in a few other cities.

I am an Uber newbie. How do I start? Do I have to download an app? I am running out of memory in my Samsung phone but have a big SD card that is nearly empty. Don't know how to add apps to the SD card, only photos.

You need to download the App. Everything is operated through it.

There's also https://m.uber.com

You'd need to create an account, first, at https://get.uber.com/sign-up - in the promo code section, use one from this thread:
http://www.flyertalk.com/forum/s-p-m...ervice-14.html

If you sign up through someone's referral link, you each get a free ride.