Can We Copy the Non-Muslims?

I'm not talking about things in the dean of Islam. I'm talking about things from the dunya, which we know that as saliz, that they're permissible. So help me, help someone at home understand, they've seized practices from the non-muslims. Are they allowed to copy them? How can they determine what they can copy them in and what they can't? If this issue has become something they're known for it, it became a sha-riyalam,. min-sha-a-a-irihim. The idea is just to get understanding close to you. It's wherever I might not be good with examples.