Insert a newline without entering in insert mode, vim

I want insert newlines in normal mode in vim using Shift-Enter and Ctrl-Enter. I try some solutions and mixing solutions from Vim Wikia - Insert newline without entering insert mode but Shift-Enter and Ctrl-Enter didn't respond:

" put a new line before or after to this linennoremap <S-CR> m`o<Esc>``nnoremap <C-CR> m`O<Esc>``" reverse J commandnnoremap <C-J> vaW<Esc>Bi<CR><Esc>k:s/\s\+$//<CR>$