document this a bit

README.md

@@ -4,6 +4,8 @@ Simple Ansible Playbooks that demonstrate how zuginfo.nrw's API can be used to s
 
 ## How to Use
 
+### Creating an account
+
 Run the Playbooks using Ansible:
 
 ```
@@ -11,4 +13,54 @@ cd zuginfo_playbooks
 ansible-playbook zuginfo_api_create_account.yml
 ```
 
-(Do the same for the other playbooks)
+Save the values to `files/account.txt` before you continue.
+
+Example:
+
+```yaml
+account:
+  aid: "12345"
+  mysterious_id: "12345"
+```
+
+### Create Subscription to your WebPush Endpoint
+
+Amend `files/account.txt`:
+
+```yaml
+account:
+  aid: "12345"
+  mysterious_id: "12345"
+  push_endpoint: "https://example.org/up/push/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+  push_key_auth: "auth_secret"
+  push_key_p256dh: "auth_key"
+```
+
+Run the Playbook:
+
+```
+ansible-playbook zuginfo_api_create_webpush_subscription.yml
+```
+
+This will return `user_id` and `channel_id`. Amend `files/account.txt`.
+
+```yaml
+account:
+  aid: "12345"
+  mysterious_id: "12345"
+  push_endpoint: "https://example.org/up/push/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+  push_key_auth: "auth_secret"
+  push_key_p256dh: "auth_key"
+  user_id: "12345"
+  channel_id: "12345"
+```
+
+### Subscribing to a specific railway line
+
+to do
+
+## Random Notes
+
+- `user_id` seems to change when all subscriptions are deleted and a new one is added
+- `channel_id` seems to change when all subscriptions are deleted and a new one is added
+- subscriptions have to be deleted before an account can be deleted