I've been using a free software called "Inkscape" to create a lot of my graphics. I'll link you to an article that helps you create isometric platforms. It will help show you where to change the angles of the boxes etc. Good luck! Software: https://inkscape.org/en/ Article: http://design.tutsplus.com/tutorial...scape-to-make-a-minecraft-scene--vector-21757
if you like the free, i suggest trying out Magicavoxel, it's a legit and solid tool to make simple items into the game. i download a game in apknite, used the tool to add items into the game to make it easier XD. very easy !
MagicaVoxel is great. The only problem I have is that getting textures out to use in BB is painful. If anyone has some steps to follow for this then please share.