Papering behind a radiator.

If possible it is best to have the radiator removed and the holding brackets too.
If the brackets are removed ensure that you note where the fixing holes are after dropping the paper over them.
First find the holes by pressing on the paper with your finger and then exposing the hole by pushing a pencil point through the paper.
If you are unable to remove the radiator the paper can be pushed gently down behind it using a dry rad roller, padded stick or more conveniently a partially used roll of wallpaper.
Make sure you have cleared and dusted down the back of the radiator before you paper.
It is a good idea to turn the radiator off long before you try to paper around it.