chore: readme updates

README.md

@@ -1,9 +1,40 @@
 # Stacks 2.0 Explorer
 
-### Getting started 
+![An image of the Stacks Explorer](/explorer-image.png 'Stacks Explorer')
 
-To run in development mode:
+### Getting started
+
+The Stacks Explorer is built with react, [next.js](https://github.com/zeit/next.js) and [@blockstack/ui](https://github.com/blockstack/ux/tree/master/packages/ui). To run the explorer locally, you can copy this repo and install the dependencies needed. Make sure you have `yarn` installed.
+
+```sh
+yarn
+```
+
+### Env variables
+
+The application needs a couple of env variables to work properly:
+
+```
+MOCKNET_API_SERVER=https://crashy-stacky.zone117x.com
+TESTNET_API_SERVER=https://sidecar.staging.blockstack.xyz
+```
+
+### Run in development mode
+
+To build and run the application, you can run this yarn task which will launch the application at http://localhost:3000.
 
 ```sh
 yarn dev
 ```
+
+### Using a local mocknet
+
+The Stacks Explorer connects to the [Stacks Blockchain](https://github.com/blockstack/stacks-blockchain) via an API server found here: [`stacks-blockchain-sidecar`](https://github.com/blockstack/stacks-blockchain-sidecar).
+The Explorer can connect and switch between a few different versions of the network: testnet, mocknet, and a local instance. To run a local instance of the Sidecar API, [please read this](https://github.com/blockstack/stacks-blockchain-sidecar/blob/master/readme.md#quick-start).
+Once you have the Sidecar API running, it should be located at `http://localhost:3999`. You can then from within your local version of the Explorer switch between the three network options:
+
+![A gif of the network switcher found within the explorer](/localhost-switch.gif 'Switching networks in the explorer')
+
+### Building for production
+
+To build for production, run `yarn build` which will run the default next.js build task.