docs: add installation and licence sections

Copied from the README, but very important to have on the website.

Author: Tygo-van-den-Hurk

docs/index.md

@@ -28,3 +28,50 @@ This would output the following fully animated presentation:
 <img src="https://raw.githubusercontent.com/Tygo-van-den-Hurk/Slyde/main/docs/assets/example-presentation.gif" width="100%" style="border-radius:var(--radius-xl);" alt="An example Slyde presentation based on the previous example XML template">
 
 To see a run down of how we made this slide [see the basics](./basics.md).
+
+## Installation
+
+There are several ways to install Slyde: [installing an npm package](#npm-package-installation), [pull docker image](#docker-image-installation), or [building from source](#building-from-source).
+
+### NPM package installation
+
+> [!NOTE]
+> This might require a token from GitHub to function.
+
+To install Slyde using [npm](https://www.npmjs.com/) from [GitHub' NPM registry](https://npm.pkg.github.com/), run the following command:
+
+```Shell
+npm install @tygo-van-den-hurk/slyde --registry=https://npm.pkg.github.com/
+```
+
+You can also install Slyde in your path by adding the `--global` flag. You might need to restart your session after installation. 
+
+### Docker image installation
+
+To install and run slyde using [docker](http://docker.com), run the following command:
+
+```Shell
+docker run --volume "$PWD:/src" --rm ghcr.io/tygo-van-den-hurk/slyde:latest compile /src/slyde.xml --output /src/slyde.html
+```
+
+### Building from source
+
+> [!WARNING]
+> This option is not recommended even if you chose to install `--global` as this makes your system harder to replicate. The previous options are recommended for almost all use cases.
+
+You can install slyde as a dependency to your project, run the following commands:
+
+```Shell
+git clone http://github.com/tygo-van-den-hurk/slyde "$PWD/slyde"
+cd "$PWD/slyde"
+npm ci
+npm run build
+cd -
+npm install "$PWD/slyde"
+```
+
+You can also install Slyde in your path by adding the `--global` flag. You might need to restart your session after installation. 
+
+## Licence
+
+All files in this repository fall under a [licence](https://raw.githubusercontent.com/Tygo-van-den-Hurk/Slyde/main/LICENSE).