Update the Getting Started tutorial

** Why are these changes being introduced:

While working with Dave on getting the network running locally during
his onboarding, we realized that the Getting Started article did not
address some things, and was slightly out of date.

** Relevant ticket(s):

n/a

** How does this address that need:

This expands the Getting Started tutorial slightly, adding information
about Composer authentication and a slightly different order of steps.

There are some additional updates as well, dealing with installation
methods and PHP versions.

** Document any side effects to this change:

None

docs/tutorial/getting-started.md

@@ -4,15 +4,15 @@ In this tutorial, you will set up a local version of our WordPress network.
 
 ## Prerequisites
 
-Please ensure you have the following tools set up on your computer. Everything
-can be installed via [Homebrew](https://brew.sh/).
+Please ensure you have the following tools set up on your computer. Most things can be installed via [Homebrew](https://brew.sh/),
+except where noted.
 
 ### PHP
 
-We currently use the latest release on the 8.0.x branch, using commands such as:
+We currently use the latest release on the 8.1.x branch, using commands such as:
 
 ```bash
-$ brew install php@8.0
+$ brew install php@8.1
 ```
 
 ### Composer
@@ -23,6 +23,28 @@ https://getcomposer.org/
 $ brew install composer
 ```
 
+You will also need to configure Composer to connect to a few [private repositories](https://getcomposer.org/doc/articles/authentication-for-private-packages.md). You will need the following:
+
+1. A Github classic token with repo scope
+
+Creating the token itself is done in [your Github account settings](https://github.com/settings/tokens/new?scopes=repo&description=For+Composer), and then registered with Composer via a command like:
+
+```bash
+composer config --global github-oauth.github.com TOKEN_VALUE_HERE
+```
+
+2. Our credentials for the Advanced Custom Fields Pro plugin
+
+These credentials can be found in our shared LastPass account, in the `Shared-Product-Pantheon` folder. They are added
+to your Composer configuration via a command like:
+
+```bash
+composer config --global http-basic.connect.advancedcustomfields.com USERNAME PASSWORD
+```
+
+When you are done with these steps, you should be able to see the results in `~/.composer/auth.json`.
+
+
 ### Terminus CLI
 
 https://docs.pantheon.io/terminus
@@ -58,21 +80,35 @@ You have done everything correctly when:
 
 https://lando.dev/
 
-```bash
-$ brew install --cask lando
-```
+Lando should _not_ be installed via homebrew. The [install instructions](https://lando.dev/download/) should be followed instead.
 
 ## Set up application
 
-- git clone mitlib-wp-network
-- composer install
-- lando pull
-- lando wp search-replace command
-- lando start
-- (optional) lando logs -f
+1. git clone mitlib-wp-network
+2. composer install
+
+If you run into problems during this phase, you may need to complete the authentication steps listed in the Composer
+section above.
+
+3. lando start
+
+While the site cannot be used yet, the containers should be running for the steps which follow.
+
+4. lando pull
+
+The `pull` command can take database and files from any tier on Pantheon, but in most cases you will want to select the
+Live tier.
+
+5. lando wp search-replace command
+
+```bash
+lando wp search-replace libraries.mit.edu mitlib-wp-network.lndo.site --url=libraries.mit.edu --network
+```
 
-Get .env from someone
+6. Load https://mitlib-wp-network.lndo.site/ in your browser. Voila!
 
-Set secrets.json values inside Lando (need more words here)
+## Please note
 
-Load https://mitlib-wp-network.lndo.site/ and see the homepage
+These instructions do not cover how to define application secrets, which mostly involve allowing WordPress to send
+emails via the WP SMTP plugin, and is rarely needed for local development. That topic is covered in the project README
+if it becomes relevant for your work.