controlling projectiles will need you to use projectile systems to create and manipulate projectiles... Berb's projectile is nice, its found on the JASS section, though you would need vJASS knowledge for it...
for models, make sure that you imported the required textures on their right path (you can learn bout them in the download page of each model)... also, save first before you try using the model... but if you already imported the model, I suggest deleting them first, then save and close your map before you fix them...