diff --git a/README.md b/README.md
index e1b111e..ae3bdff 100644
--- a/README.md
+++ b/README.md
@@ -10,9 +10,9 @@ The following is required or suggested:
 
   * OpenBSD (or another BSD or some Linux distro) with HTTPD and NSD installed (pkg_add nsd), configured and running
   * (sub-)domain for your webserver. Needed for updating the NS record of your actual DynDNS domain.
-    * In this example: update.example.com
+    * In this example: _update.example.com_
   * (sub-)domain that is updated dynamically. 
-    * In this example: dyn.example.com
+    * In this example: _dyn.example.com_
   * A router capable of sending custom GET-requests to your DynDNS server.
     * In this example: A FritzBox
  
@@ -20,7 +20,7 @@ The following is required or suggested:
  
  ### Configure your HTTPD
  
- Add the following new virtual host to your /etc/httpd.conf:
+ Add the following new virtual host to your _/etc/httpd.conf_:
  
 ```
  server "update.example.com" {
@@ -30,7 +30,7 @@ The following is required or suggested:
 }
 ```
  
-Create an empty index.html:
+Create an empty _update.html_:
  
 ```
 # mkdir /var/www/htdocs/dyndns/
@@ -38,11 +38,11 @@ Create an empty index.html:
 ```
 
 After reloading HTTPD, try to access http://update.example.com/update.html
-The request should show up in /var/www/logs/dyndns.log
+The request should show up in _/var/www/logs/dyndns.log_
 
 ### Create a zone file for dyn.example.com
 
-Create a new zone file (e.g. at /var/nsd/zones/dyn.example.com.zone) with the following content
+Create a new zone file (e.g. at _/var/nsd/zones/dyn.example.com.zone_) with the following content
 
 ```
 $ORIGIN example.com.
@@ -65,7 +65,7 @@ dyn IN A 123.123.123.13
 ```
 
 Don't forget to set your own domain names, name servers and ip addresses
-Furthermore, add this zone file to your /var/nsd/etc/nsd.conf
+Furthermore, add this zone file to your _/var/nsd/etc/nsd.conf_
 
 ### Configure and Install nsd-dyndns
 
@@ -75,10 +75,35 @@ Furthermore, add this zone file to your /var/nsd/etc/nsd.conf
   * Make the script executable:
     * _# chmod u+x /usr/local/bin/dyndns.sh_
   * Add _/usr/local/bin/dyndns.sh_ to your crontab
-  
+
+### Configure your router
+
+Configure your router to query the following URL:
+
 ```
+update.example.com/update.html?qwertzuiop1234567890
+```
+
+Don't forgert to set your own domain name and to replace the string after "?" with the password you configured in the config file.
+
+### What it does
+
+When your router gets a new IP and therefore sends an HTTP request to your server, a similar entry should appear in your _/var/www/logs/dyndns.log_:
+
+```
+update.axample.com 123.123.123.123 - - [29/Apr/2018:20:48:19 +0200] "GET /update.html?qwertzuiop1234567890 HTTP/1.1" 200 6
+```
+
+When the script is executed e.g. via cron, the following happens:
+  * It greps the last line of _/var/www/logs/dyndns.log_ where the correct password was found and extracts the requesting IP address
+  * It checks if this IP is the same than the last time
+  * If it's a new IP, then it replaces the forth line in your zone file - the line with the version number - with a new version (current unix time stamp)
+  * As a second step, it updates the A record of you DynDNS domain (dyn.example.com in our example)
+  * It then stores the new IP in the file _/tmp/last_dyndns_ip.txt_
+  * Finally it reloads NSD
+
  
-```
+