chore(cozy-dataproxy): Improve README

packages/cozy-dataproxy/README.md

@@ -1 +1,29 @@
 # Cozy-dataproxy
+
+## Concept
+
+This library is meant to be used by DataProxy apps like [cozy-web-data-proxy](https://github.com/cozy/cozy-web-data-proxy) or [cozy-flagship-app](https://github.com/cozy/cozy-flagship-app). Its goal is to mutualize data manipulation features like Search indexing
+
+## Installation
+
+Just run
+
+- `yarn add cozy-dataproxy`
+
+## API
+
+### Nomenclature
+
+- `SearchEngine`: Class that can index and search through Cozy's metadata
+
+### Setup and usage
+
+In order to create a SearchEngine:
+```ts
+  const searchEngine = new SearchEngine(client)
+
+  // ...
+
+  const query = 'Some search string'
+  const searchResult = searchEngine.search(query)
+```