Improve notes for instruction to create a user account

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/installing.md

@@ -77,8 +77,9 @@ After creating the user account, you can log in to it with [Element Web](configu
 To register a user via this Ansible playbook, run the command below on your local computer.
 
 **Notes**:
-- Before running it, make sure to edit `YOUR_USERNAME_HERE` and `YOUR_PASSWORD_HERE`
-- In the command below, `YOUR_USERNAME_HERE` is just a plain username (like `john`), not your full `@user:example.com` identifier
+- Make sure to edit `YOUR_USERNAME_HERE` and `YOUR_PASSWORD_HERE`
+- To `YOUR_USERNAME_HERE`, set a plain username like `john`, not your full `@user:example.com` identifier
+- Set `admin=yes` to make the user an administrator of the Matrix server
 
 ```sh
 ansible-playbook -i inventory/hosts setup.yml --extra-vars='username=YOUR_USERNAME_HERE password=YOUR_PASSWORD_HERE admin=<yes|no>' --tags=register-user

docs/quick-start.md

@@ -117,8 +117,9 @@ As you have configured your brand new server and the client, you need to **creat
 To register a user via this Ansible playbook, run the command below on your local computer.
 
 **Notes**:
-- Before running it, make sure to edit `YOUR_USERNAME_HERE` and `YOUR_PASSWORD_HERE`
-- In the command below, `YOUR_USERNAME_HERE` is just a plain username (like `john`), not your full `@user:example.com` identifier
+- Make sure to edit `YOUR_USERNAME_HERE` and `YOUR_PASSWORD_HERE`
+- To `YOUR_USERNAME_HERE`, set a plain username like `john`, not your full `@user:example.com` identifier
+- Set `admin=yes` to make the user an administrator of the Matrix server
 
 ```sh
 ansible-playbook -i inventory/hosts setup.yml --extra-vars='username=YOUR_USERNAME_HERE password=YOUR_PASSWORD_HERE admin=<yes|no>' --tags=register-user