📝 Document how to install and preview changes locally

 sphinx-autobuild docs/EN docs/_build/html

README.md

@@ -1,13 +1,58 @@
 Repository for [Trio documentation (under development)](https://docs.diy-trio.org)
 
+## Install
+
+- [Clone](https://docs.github.com/en/repositories/creating-and-managing-repositories/cloning-a-repository) this project
+- Install *Python* 3
+ Review [Properly Installing Python](http://docs.python-guide.org/en/latest/starting/installation/) for help on getting *Python* installed.
+- Install a Python Virtual Environment. 
+ In this example, I use [`venv`](https://realpython.com/python-virtual-environments-a-primer/#how-can-you-work-with-a-python-virtual-environment), but use whichever you prefer.
+
+```shell
+cd trio-docs # cd into the folder where you cloned this repository
+
+# Creates a virtual environment using Python 3 in the venv folder
+python3 -m venv venv
+
+# Activate the virtual environment
+# Run the next line **each time** you start a new shell window/tab
+source venv/bin/activate
+
+# Make sure you are in the folder where you cloned this repository, if not:
+# cd trio-docs
+
+# To build and preview the site locally (hot-reload the pages in the Web browser)
+python -m pip install sphinx-autobuild
+
+# Install the project's required packages
+python -m pip install -r requirements.txt
+```
+
+## Run
+
+Once [installed](#install), you can preview the doc locally as you edit.
+
+### Preview Changes Locally
+
+To preview your work as you edit, run this command in a separate terminal window/tab and do not interrupt it:
+
+ ```shell
+ # cd trio-docs # cd where you cloned this repository
+
+ sphinx-autobuild docs/EN docs/_build/html
+ ```
+
+ This builds the site locally and **runs a local Web server** on http://127.0.0.1:8000 
+ It also rebuilds the site when you change a file and hot refreshes the browser so that you can see the changes.
+
 ## Tips & Tricks
 
-> [!NOTE] 
+> [!NOTE]
 > Please add!
 
 ### Add a Chapter
 
-Using the `#` sign shows a chapter on the menu/index. The amount of `#`'s determines the level. 
+Using the `#` sign shows a chapter on the menu/index. The amount of `#`'s determines the level.
 
 **Example**:
 
@@ -21,15 +66,16 @@ Using the `#` sign shows a chapter on the menu/index. The amount of `#`'s determ
 ### Link to Another File
 ```
 
-> [!TIP] 
+> [!TIP]
 > If you want to avoid a chapter ending up in the menu/index, use bold text by:
-> - either surrounding the text with 2-star signs `**` 
-> - or adding `<b>` before the text and `</b>` after the text (without spaces). 
-> 
-> Input | Result 
-> ------------------ | ------------- 
-> `**bold text**` | **bold text** 
->  `<b>bold text</b>` | **bold text** 
+>
+> - either surrounding the text with 2-star signs `**`
+> - or adding `<b>` before the text and `</b>` after the text (without spaces).
+>
+> | Input | Result |
+> | ------------------ | ------------- |
+> | `**bold text**` | **bold text** |
+> | `<b>bold text</b>` | **bold text** |
 
 ### Link to Another File