Update README with instructions for running with OpenSearch (#235)

* Update README with instructions for running with OpenSearch

updated README with download and setup instructions for both OpenSearch
and Dashboards.

Closes #223

Signed-off-by: Bishoy Boktor <boktorbb@amazon.com>

* Address PR comments

Signed-off-by: Bishoy Boktor <boktorbb@amazon.com>

* Address PR comments

Signed-off-by: Bishoy Boktor <boktorbb@amazon.com>

README.md

@@ -35,6 +35,23 @@ We officially began work on the new fork on January 21st, 2021. Since then, we'v
 * **Respectful, approachable, and friendly.** This will be a community where you will be heard, accepted, and valued, whether you are a new or experienced user or contributor.
 * **A place to invent.** You will be able to innovate rapidly. This project will have a stable and predictable foundation that is modular, making it easy to extend.
 
+## Getting Started
+
+To run OpenSearch Dashboards locally, you first need build artifacts from OpenSearch.
+* Clone the OpenSearch repo with ```git clone git@github.com:opensearch-project/OpenSearch.git```
+* Follow installation and setup instructions in the OpenSearch repo
+* Run ```./gradlew assemble``` to generate build artifacts for all platforms
+* Run ```./gradlew run -Drun.distribution=oss``` to run the oss build
+
+Or
+* You can also manually find the tar.gz file (.zip on Windows) at ```./distribution/archives/<platform-dir>/build/distributions``` and extract to your desired directory with ```tar -xvf /path/to/tar/file```
+* After extracting, run ```bin/opensearch``` inside of the extracted build artifact dir
+
+To run Dashboards with OpenSearch
+* Run ```yarn osd bootstrap``` in the OpenSearch Dashboards directory
+* While OpenSearch is running locally, run ```yarn start --oss```
+* You can now navigate to ```http://localhost:5601``` where Dashboards runs by default
+
 ## How you can help
 
 ### Look for the label "help wanted"