[VBLOCKS-4113] chore: clarify handling of env vars (#30)

* chore: clarify handling of env vars

* feat: add guide for bash zsh

* chore: add note for source

Author: kpchoy

README.md

@@ -10,7 +10,13 @@ Twilio Voice JavaScript Reference Components leverages [Web Components](https://
 git clone https://github.com/twilio/twilio-voice-js-reference-components.git
 ```
 
-2. Create a `.env` file and initialize the following environment variables under the `twilio-voice-js-reference-components` folder. Go through the [quickstarts](https://www.twilio.com/docs/voice/sdks/javascript/get-started) for more information about these variables.
+2. Install the dependencies.
+
+```bash
+npm install
+```
+
+3. Create a `.env` file and initialize the following environment variables under the `twilio-voice-js-reference-components` folder. Load the `.env` variables into `process.env` based on your specific platform. Go through the [quickstarts](https://www.twilio.com/docs/voice/sdks/javascript/get-started) for more information about these variables.
 
 ```bash
 # Port number to run the server on
@@ -43,10 +49,17 @@ CALLBACK_BASE_URL=https://foo.ngrok.dev
 DEFAULT_IDENTITY=alice
 ```
 
-3. Install the dependencies.
+- For example, if you're using `bash/zsh` format your `.env` like so:
 
 ```bash
-npm install
+export ACCOUNT_SID=ACxxxxxxxxxxxxxx
+```
+
+- Then, under the `twilio-voice-js-reference-components` folder run:
+  - Note: running `source .env` will cause environment variables to persist in your shell session, and will be available to all processes afterwards.
+
+```bash
+source.env && npm run start
 ```
 
 ## Run the project locally

package.json

@@ -2,7 +2,7 @@
   "name": "twilio-voice-js-reference-components",
   "version": "1.0.0",
   "scripts": {
-    "start": "source .env && node src/server.js"
+    "start": "node src/server.js"
   },
   "type": "module",
   "engines": {