Update ACCESS_TOKENS.md

ACCESS_TOKENS.md

@@ -1,7 +1,7 @@
 # Access Keys & Tokens for mmm-nest-status
 
 ## Which Keys & Tokens Do I Need?
-You'll need 4 of them:
+You'll need these 4:
 - Google Cloud Platform OAuth 2.0 Client ID
 - Google Cloud Platform OAuth 2.0 Client Secret
 - Device Access Project ID
@@ -11,10 +11,43 @@ You'll need 4 of them:
 
 Well, the easiest way is to simply follow Google's [Device Access Quick Start Guide](https://developers.google.com/nest/device-access/get-started). You will, of course, need a Google acount in order to do so.
 
-More stuff here ...
+If you go through Step 1 (Get Started) and Step 2 (Authorize an Account), it should provide you with the necessary keys and tokens.
+
+## Is This a Difficult Process? Can You Help?
+
+It really depends on your technical knowledge & skill level. I'm fairly tech-savvy and there were still a couple of areas during the process I felt a bit stumped.
+
+With that said, here are the steps I took in order to get this working on my own mirrors:
+
+1. Register for Device Access in the [Device Access Console](https://console.nest.google.com/device-access). You'll need to pay a one-time fee of $5.
+2. Enable the API & get an OAuth 2.0 Client ID for a Google Cloud Platform project
+  - I'd suggest using the `Enable the API and get an OAuth 2.0 Client ID` button that's on the `Get Started` page of the Quick Start Guide I linked above - it's much easier than doing it inside the Google Cloud Console.
+  - Make sure to choose `Web Server` when it asks "Where are you calling from?" and to enter `https://www.google.com` as the value for Authorized redirect URIs. If you don't, the next step will fail.
+  - Save the `OAuth Client ID` and `OAuth Client Secret` values for later - you'll need them for the main `config.js` file in your MagicMirror installation and also to get the refresh token.
+3. Go to the [Device Access Console](https://console.nest.google.com/device-access) and create a new project.
+  - Pick a name (doesn't really matter what it is), then add the `OAuth Client ID` that was generated in the previous step.
+  - I don't use Events in this module, so whether you enable/disable them is up to you.
+  - Once you're done, you'll get a `Project ID` which you'll add to the the main `config.js` file in your MagicMirror installation.
+4. Link your account using the instructions on the [Authorize an Account page](https://developers.google.com/nest/device-access/authorize).
+  - Make sure you're using the `Project ID` you just generated and the `OAuth Client ID` from Step 2 above.
+  - I would suggest you enable **all** permissions for **all** devices (saves you from having to do this again if you're also using my `mmm-nest-cameras` module), but, technically, you only need to enable access to your thermostats in order for this module to work.
+  - Once you've confirmed your choices, you'll be redirected to `google.com` and your URL will contain an `authorization code` you'll need for the next (and final) step. Make sure to copy that code before navigating away from that page.
+5. Get an access token using the instructions on the [Authorize an Account page](https://developers.google.com/nest/device-access/authorize).
+  - You can either do this in your `terminal` using curl (as the example shows on the page) or use a dedicated REST client like [Postman](https://www.postman.com).
+  - If everything goes according to plan, you should get a JSON response that contains both an `access_token` and a `refresh_token`. This module only uses the `refresh_token`, so feel free to ignore everything else.
+
+That's it - you should now have:
+- Google Cloud Platform OAuth 2.0 Client ID from Step 2
+- Google Cloud Platform OAuth 2.0 Client Secret from Step 2
+- Device Access Project ID from Step 3
+- Device Access Refresh Token from Step 4
+
+Add them to the `config.js` file in your MagicMirror installation and you should be good to go:
+
+![image](https://user-images.githubusercontent.com/3209660/144290713-c4b0d3cb-68bc-4a66-912b-0887f1e3793a.png)
 
 ## Can I Use My Old Nest Developer Account With This Module?
 
 The 2.x version of this module **only** supports the [Google Device Access API](https://developers.google.com/nest/device-access).
 
-If you still have an old Nest developer account, you'll need to either migrate it to Google or use the [`1.4.3`](https://github.com/michael5r/mmm-nest-status/tree/1.4.3) version of this module.
+If you still have an old Nest developer account, you'll need to either migrate it to Google or use the [`1.4.3`](https://github.com/michael5r/mmm-nest-status/tree/1.4.3) version of this module.