Add first tutorial

[stevevanhooser]

Hi Yijia -

I wondered if you could take a stab at writing the first tutorial (on the yijia_docs branch). I added the structure for documentation and posted preliminary documentation to the web (see http://ndr.vhlab.org). The documentation is also found in markdown files in our distribution, in the new docs folder.

The pages are written in a form of simplified html called markdown. You can read about how to write in markdown here (https://www.markdownguide.org/cheat-sheet/). It's pretty straightforward. You can also Google about how to write a document in markdown.

Why don't you take a stab at showing a new user how to read from a channel. You can write words and also include example code in code blocks (see how markdown has you write a code block).

The file to edit is docs/tutorial/readanalog.md

The tutorials will be simpler than those we are writing for using NDI. You can see one of those tutorials here for inspiration: https://vh-lab.github.io/NDI-matlab/tutorials/analyzing_first_physiology_experiment/1_example_dataset/

The preliminary documentation is up at ndr.vhlab.org. Your changes won't immediately go through to the website; I'll need to post them from the repo.

If you want to preview what you've done, you can download a Chrome extension for markdown and open the file on your computer in Chrome.

Thanks!
Steve