Place folders in C:\Program Files\Steam\steamapps\**USERNAME**\team fortress 2\tf

The full Address for the model is C:\Program Files\Steam\steamapps\**USERNAME**\team fortress 2\tf\models\weapons\c_models\c_ambassador

The full Address for the textures are C:\Program Files\Steam\steamapps\**USERNAME**\team fortress 2\tf\materials\models\weapons\c_items

If you don't have the folders, make them.