First of all Plasma_snake, your title of this thread is weird. Mind changing it to right topic?
Now, when you want to access router settings, open a browser and type 192.168.1.1 in the address bar. A authentication box will appear asking for username and password. Type 'admin' both as username and password (without quotes). You will be able to access the configuration pages then. Go to 'Interface Setup' tab and under 'Internet' (automatically selected), look for 'Encapsulation'. There will be 4 options under ISP and select PPPoA/PPPoE from them.