diff --git a/README.md b/README.md
index bfe867831c2b163a2280cb186c84b1fc35cc4492..1f5acb9fbc947b3dec143cfc0a2a485cffd12ee8 100644
--- a/README.md
+++ b/README.md
@@ -17,3 +17,11 @@ For Google APIs and these credentials should correspond to a user with owner or
 editor access to the target project. You can use the ``gcloud`` command line
 tool to set your personal credentials as application default credentials. See
 the ``gcloud auth application-default`` command output for more information.
+
+## Custom domain mapping
+
+Setting the `dns_name` will create a domain mapping for the webapp. Before
+setting this value you *must* have verified ownership of the domain with Google.
+[Instructions on how to do
+this](https://guidebook.devops.uis.cam.ac.uk/en/latest/notes/google-domain-verification/)
+can be found in the DevOps division guidebook.
diff --git a/main.tf b/main.tf
index bbb33de91a046632ce1528792fce8dbba96783f0..55fb96c7a01a0774e3bf2aa2da68d44946a82d42 100644
--- a/main.tf
+++ b/main.tf
@@ -109,7 +109,7 @@ resource "google_cloud_run_service_iam_member" "webapp_all_users_invoker" {
 
 # Domain mapping for default web-application. Only present if the domain is
 # verified. We use the custom DNS name of the webapp if provided but otherwise
-# the webapp is hosted at [SERVICEN NAME].[PROJECT DNS ZONE]. We can't create
+# the webapp is hosted at [SERVICE NAME].[PROJECT DNS ZONE]. We can't create
 # the domain mapping if the domain is *not* verified because Google won't let
 # us.
 resource "google_cloud_run_domain_mapping" "webapp" {
diff --git a/variables.tf b/variables.tf
index 05bcaa754a9bd26cbdd51391c74c23655235f442..be7f5b0798c758d4c9e8797a03279f3a185bbb8a 100644
--- a/variables.tf
+++ b/variables.tf
@@ -61,7 +61,7 @@ variable "dns_name" {
   description = <<EOI
 If non-empty, a domain mapping will be created for the webapp from this domain
 to point to the webapp. The domain must first have been verified by Google and
-the account being used by the google provider nust have been added as an owner.
+the account being used by the google provider must have been added as an owner.
 
 If and only if a domain mapping has been created, the
 "domain_mapping_resource_record" output will be a non-empty map and the