Understanding Vim commands on paper as keyboard actions

Question

I am having problems understanding how Vim commands are supposed to be executed as keyboard actions. This is a topic I don't see being discussed often. Some examples are:

<s-tab>

I believe this is s + tab but I don't get the expected results.

<c-k>

I believe this is ctrl + k.

<C-k>

I sometimes see uppercase c but what is the difference?

And, inside of a Vim .vimrc file:

noremap <D-M-Left> :tabprevious<cr>
noremap <D-M-Right> :tabnext<cr>
nnoremap <c-j> <c-w>j
map <D-1> 1gt

My questions are:

1. What does the case of a letter have to do with the command?
2. Do the "<" ">" braces represent any action?
3. Does the "-" dash represent any action?

Answer 1

I think :help key-notation will answer all of your questions about this topic.