For the basics the tutorial that comes with stock emacs is GOAT. You navigate the tutorial in the program you’re learning the navigation in, that’s how I learned it. It covers the basics, moving, killing/yanking (cutting/pasting), moving the view without moving the point (the cursor), handling buffers (open files), windows (subframes in the emacs window) and frames (multiple emacs windows). There is a bit of a translation required as emacs is old and some terms come from a time before the concepts were in common english but it’s nothing really. I’m rather new to emacs as well, and this is how I learnt it.
After that what I found most useful was the following packages
(require 'use-package)
(require 'diminish)
(require 'bind-key)
(use-package eldoc)
(use-package which-key
:bind ("M-H" . which-key-show-top-level)
:init (which-key-mode t)
:config (which-key-setup-side-window-right-bottom))
(use-package marginalia :init (marginalia-mode))
(use-package embark :bind ("C-<return>" . embark-act)
:custom (prefix-help-command #'embark-prefix-help-command))
(use-package embark-consult
:hook (embark-collect-mode consult-preview-at-point-mode))
This binds Alt+H to show all the keys available (use Ctrl+h n to scroll) as well as automatically pops up a buffer when you entered a command that isn’t complete, e.g. Ctrl+x. And it binds Ctrl+Return to a kind of right-click menu that tries to guess at all the actions you could do with the thing you have at under the point.
But most useful, is Ctrl+h f to describe what a function does and Ctrl+h v to describe what a variable does as well as the customize menu Alt+x customize.
For a theme I would suggest one of ef-themes but that’s up to you ofcourse. Org-mode’s export really is awesome though.
Emacs is a bit daunting to set up but I’m really loving it. See also https://github.com/SystemCrafters/crafted-emacs/tree/master for some ideas for how to set up some other stuff, although I went with the stock completions.
There are also non-emacs ways of interacting with org files https://orgmode.org/tools.html but I don’t know anything about them.