Hi all, I'm building a wood fired oven on a concrete base, and am about to start on the supporting wall, which will be made from hollow concrete blocks (heavy). The blocks will be filled with concrete. As I doubt I can lay each block level, I will need to bed them down with mortar, so that I can level them. having never laid a brick or block before, any advice that you can offer? Obv the mortar mix must not be too soft, but if there are any tips you can offer, they'd be much appreciated! Cheers