feat: adding readme block with instructions to main page

packages/testing-docs/docs/intro.md

@@ -7,3 +7,43 @@ sidebar_position: 1
 \<-- Use left sidebar for navigation
 
 ![Screenshot](../static/img/main.png)
+
+# How to contribute to project
+
+## What you'll need
+
+- [Node.js](https://nodejs.org/en/download/) version 18.0 or above:
+  - When installing Node.js, you are recommended to check all checkboxes related to dependencies.
+
+## Project structure rundown
+There are few important entities existing in the Docs folder `packages/testing-docs` you need to know about:
+ - `/docs`- Contains the Markdown files and text content for the docs.
+ - `/static` - Non-documentation files (screenshots/images mostly) that are used in Markdown files.
+
+## How to contribute to project
+- Clone [Block Explorer repository](https://github.com/matter-labs/block-explorer)
+- Run the next command in the root Block Explorer folder to install all required dependencies:
+```bash
+npm install
+```
+- Go to `packages/testing-docs` folder
+- Run 
+```bash
+npm run build
+```
+- Run 
+```bash
+npm run serve
+```
+- Local Docs project will be available at [`http://localhost:3000/docs/intro`](http://localhost:3000/docs/intro)
+- Find a page/element you want to edit and proceed with your changes
+
+### Editing Docs
+To get familiar with markdonwn features visit [Docusaurus Guides](https://docusaurus.io/docs/markdown-features) page
+
+### Creating a PR
+After making changes to the project 
+- create a pull request with your changes
+- make sure all the checks passed (all have to be green)
+- request a review from a QAs
+After successull review PR with changes will be merged to main branch