Just play it ... :D 

The aim of the game is to kill the creeps before they reach the end of the maze, do this by building attacking towers on the grass around the maze. To build click on the one you want to build on the right, then click on the map where you want it to be built. Once built you can click on them to upgrade or sell. To get a high score keep as much of your gold in the bank as possible, at the end of each round you earn interest on the gold in the bank. Special levels are where the creeps are none-normal, they include FAST [6, 13, 19, 26, 32] AIR [8, 17, 27] IMMUNE [10, 21, 32] BOSS [11, 22, 33] You get wood every 7 levels use wood to research upgrades. For more game info & tips visit the Instructons & Tips section