Update billing alerts docs for new standalone page

src/pages/docs/platform/pricing/billing.mdx

@@ -45,8 +45,8 @@ Billing alerts notify you by email when your monthly spending exceeds a set amou
 The following steps guide you through setting up billing alerts:
 
 * Log in to your Ably [account.](https://ably.com/login)
-* In the [Create new alert](https://ably.com/accounts/any/package#billing-alerts-section) section, select the email address from the dropdown list where you want to receive the alert. The available choices depend on your [user role](/docs/platform/account/users#roles).
-  * If you are an owner: Yourself and billing users associated with the account.
-  * If you are a user with a billing role: Yourself only.
-* Enter a value greater than your base package fee in the *Amount* field. This amount sets the threshold at which you will receive a notification.
-* Click *Create alert* to save your changes.
+* Navigate to the [Billing alerts](https://ably.com/accounts/any/billing_alerts) page under the *Billing* section in the sidebar.
+* Click *Create alert* to open the alert form.
+* If you are an account owner, select the recipient from the *Recipient* dropdown. You can create alerts for yourself or any billing user associated with the account. If you are a billing user, alerts are created for yourself automatically.
+* Enter a dollar amount greater than your base package fee in the *Amount* field. This sets the spending threshold at which you will be notified.
+* Click *Create alert* to save.