Improve README: contents, structure, formatting

- add to, update contents
- improve document structure, readability of headlines
- switch to more generic code formatting

README.md

@@ -1,28 +1,44 @@
-# app template
+# Template for Nuxt 3 applications
 
-template repository for nuxt 3 apps.
+Skeleton app for new Nuxt 3 apps developed at [ACDH-CH](https://www.oeaw.ac.at/acdh/acdh-ch-home).
 
-## how to run
+## Prerequisites
 
-prerequisites:
+You need to have **Node.js** and **pnpm** installed on your system to base your own projects on this example app.
+
+For download and install instructions, see:
 
 - [Node.js v18](https://nodejs.org/en/download)
 - [pnpm](https://pnpm.io/installation)
 
-set required environment variables in `.env`:
 
-```bash
-cp .env.example .env
+## Setup
+
+### Configure environment variables
+
+Use file `.env.example` at the root of the repository to create a new file named `.env` to store local environment variables:
+
+```sh
+cp -n .env.example .env
 ```
 
-install dependencies:
+Adapt the new file's contents to your project/dev environment.
+
 
-```bash
+### Install dependencies
+
+Run the following command to install all required dependencies:
+
+```sh
 pnpm install
 ```
 
-run a development server on [http://localhost:3000](http://localhost:3000):
+## Usage
 
-```bash
+To run the app, use:
+
+```sh
 pnpm run dev
 ```
+
+You should now be able to access your application at the address provided via `NUXT_PUBLIC_APP_BASE_URL`  in your `.env` file.  The default address given in the example file is [http://localhost:3000](http://localhost:3000).