Custom models won't show up in game

[str4wberrypanic]

So, i was messing around with the model editor for the first time, and all i wanted was to remove the music from an enemy and make a plate unbreakable. And that's what i did, unmarked the " breakable " option and removed the music. Then i saved with another name and placed them in the level editor. However these entities won't appear in-game. Where did i went wrong?