Parent theme doesn't appear in wp-admin themes, can't I just edit parent theme?

Hi, (bit of a read here, sorry for that but I’m out of options really)

So I have been trying to create a child theme for hours now, and my frustration is so high now that I have started crying (sorry if I sound pathetic, but couldn’t care less at the moment).

I’m working on mac os with MAMP in safari ( in case this is of any use)

I’m trying to work with the theme Sundance, so this is what I have done up till now.
-Downloaded the sundance theme, which is sitting in my wp-content folder
-in that same folder I created a second folder named sundance-child, in which I created the file style.css using “Brackets”
In the file I typed the following:
/*
Theme Name: Sundance Child
Theme URI:
Description:
Author:
Author URI:
Template: sundance
Version:
Tags:
Text Domain:
*/

-went into my browser, refreshed my wp-admin panel, and checked in the theme and the child, is not there. But the the parent theme sundance itself is present.
(Might be good to mention that I have removed all other theme files in the wp-contents folders that were not related to the sundance theme that I am looking to install)

– now after the first time that this happened, I have tried many different ways of creating that damn css file for the child, but nothing keeps happening. After 3 hours of following every instructions, step by step, and reading all previous threads about the subject without success , I have decided to quit trying to create a child theme.

It’s a downright pain in the ass, to say the least.

But my question now is, if I just make changes straight into the theme, is it really such a big deal. Basically what I need to know, is do updates to themes happen automatically or do I have to instal them myself? And if it’s the later, and I don’t decide to update my theme, so as to keep the changes I’ve made in the original file, what is the worst that could happen.

Oh, and if you happen to know what I’ve done wrong with the whole child theme thing, feel free to let me know.

Thank you,

I am going to cry myself to sleep now…