How do you finally setup your 2862 ?

I need to do something similar. I was thinking it needs to be setup in passthrough but I am not sure anymore. UK Based so really I need a PPPoE to PPPoA, a bit like what the Vigor 130 does. As I already have a 2862, I was thinking it should be a similar setting. Still do not understand how I should set it up, nor how I access the configuration once passthrough is enabled.

Thanks

JM