chore: add usage to readme

Co-authored-by: Maxime Mangel <[email protected]>

Author: jkone27

README.md

@@ -2,6 +2,52 @@
 
 This is a compiler from `.d.ts` to F# bindings for [Fable](https://fable.io/).
 
+## Getting Started
+
+Glutinum is delivered both as a CLI tool and web interface.
+
+### Web Interface
+
+The web interface is available [here](https://glutinum.net/).
+
+It is a simple and easy-to-use tool, allowing you to convert `.d.ts` files to F# bindings directly from your browser without installing anything.
+
+This is also the tool that you should use to report issues if possible.
+
+💡 The web interface is more often updated than the NPM package
+
+### CLI via NPM
+
+The CLI can be invoked using `npx`:
+
+```bash
+npx @glutinum/cli --help
+```
+
+or installed locally:
+
+```bash
+npm i -D @glutinum/cli
+```
+
+### Usage
+
+```bash
+# Without installing the package
+npx @glutinum/cli ./node_modules/my-lib/index.d.ts --out-file ./Glutinum.MyLib.fs
+# Or with the installed package
+npx glue ./node_modules/my-lib/index.d.ts --out-file ./Glutinum.MyLib.fs
+```
+
+or if you prefer you can pipe the output to a file:
+
+```bash
+# Without installing the package
+npx @glutinum/cli ./node_modules/my-lib/index.d.ts > ./Glutinum.MyLib.fs
+# Or with the installed package
+npx glue ./node_modules/my-lib/index.d.ts > ./Glutinum.MyLib.fs
+```
+
 ## Contributing
 
 Glutinum.CLI use `./build.sh` or `./build.bat` as a build script.