Knife models don't appear

I haven’t used Studio in years, and I almost completely forgot how to use it. Anyway, I’m trying to add some models to the game but whenever I join I don’t see these models, every knife I tried putting in the game dissapears.
What I’m trying to do is put all the models needed for me to make a game, and could I just download their models from the catalog and then add whatever scripts I want?
It’s a stupid question yeah, but I didn’t know where to ask.

Soo… Does anyone have a suggestion???

you probably forgot to anchor them. anchor the models and let me know if its fixed.