Bibi637

Hello I've just started to follow the PMC tutorial to learn how to build terrain, but when it comes to step bulldozer step when i load bulldozer this terrain shows up https://image.noelshack.com/fichiers/2019/31/4/1564687218-nouvelle-image-bitmap.png I followed everything to the letter but this don't work, I searched over the forum and on google but i didn't found anything ... can someone help me please ? (sorry for my english i'm french)