For a very simple reverse proxy, all you have to do is:
1. Select the server node on inetmgr.
2. Double click on Application Request Routing icon.
3. Select/check "Enable proxy".
4. Select/check "Use URL Rewrite to inspect incoming requests.
5. Enter the server of where you want to route the request to in "Reverse proxy" - ie. (myserver.contoso.com).
In above example, all requests that are received by ARR will be routed to myserver.contoso.com.