The older puppies (Dally the Aussalier & Maisie the Cavapoo) have seen and played with the garbage can lid before. But it was the plastic one. This metal one is much noisier! So to make it less annoying as they learn about it, I put a towel underneath. Plus I added some cheese to entice them to check out the new contraption.
And we have continued to have some playtime in the backyard with the horses closeby so Dally gets accustomed to the big creatures.