Merge pull request #1 from iFurySt/docs/harness-cli-install-readme

docs: add harness-cli setup instructions

Author: usoonees

README.md

@@ -13,12 +13,21 @@ Use GitHub's template flow from the top right of this repository:
 1. Select **Use this template**.
 2. Select [**Create a new repository**](https://github.com/new?template_name=harness-template&template_owner=iFurySt).
 
-Or initialize a new or existing repository with `harness-cli`:
+Or initialize a new or existing repository with [`harness-cli`](https://github.com/iFurySt/harness-cli).
+Install it from npm first:
+
+```sh
+npm install -g @ifuryst/harness-cli
+```
+
+Then run:
 
 ```sh
 harness-cli init --language en
 ```
 
+`harness-cli` requires Node.js 18+ and Go on your `PATH`.
+
 ## License
 
 [MIT](LICENSE)