Backing boards - Tile Advice

[New to tiling]

Please help - I am tiling my bathroom and have read I need to put Harvey backer cement boards on (round the shower) and then moisture resistance board round the rest of the bathroom - do you agree - if so where do you guys buy the water resistance board from? Or.... would you tank it?

 

[Dave]

Please help - I am tiling my bathroom and have read I need to put Harvey backer cement boards on (round the shower) and then moisture resistance board round the rest of the bathroom - do you agree - if so where do you guys buy the water resistance board from? Or.... would you tank it?

Just use PB. And tank it.