Add documentation (#2)

Author: JosephusPaye

README.md

@@ -1,3 +1,41 @@
 # nbsjs
 
-Node.js module for interacting with NUClear Binary Stream files
+[![Node.js CI](https://github.com/Fastcode/nbsjs/actions/workflows/node.js.yml/badge.svg?branch=main)](https://github.com/Fastcode/nbsjs/actions/workflows/node.js.yml)
+
+Node.js module for interacting with [NUClear Binary Stream](https://nubook.nubots.net/system/foundations/nuclear#nbs-files) files.
+
+## Installation
+
+The package contains a native module, so you'll need a working C++ compiler on your system to install and build it.
+
+```
+npm install nbsjs --save
+```
+
+## Usage
+
+The following example shows a typical usage pattern of creating a decoder with nbs file paths, and reading types, timestamps, and data packets.
+
+```js
+const { NbsDecoder } = require('nbsjs');
+
+// Create a decoder instance
+const decoder = new NbsDecoder(['/path/to/file/a.nbs', '/path/to/file/b.nbs', '/path/to/file/c.nbs']);
+
+// Get a list of all types present in the NBS files, and get the first type
+const types = decoder.getAvailableTypes();
+const firstType = types[0]
+
+// Set the timestamp range for the first available type
+const [start, end] = decoder.getTimestampRange(firstType);
+
+// Get the packet at the given timestamp for the first type
+const packets = decoder.getPackets(start, [firstType])
+
+// Log all the values for inspection
+console.log({ types, firstType, start, end, packets })
+```
+
+## API
+
+See [`nbs.d.ts`](./nbs.d.ts) for API and types.