Placing Prefabs

 

If you have selected some asset packages before creating the project you should just see some files loaded into your project browser,

as showed into the following image:

You can click on blue folders for opening directories containing other files.

 

Prefabs are the assets with a green triangle on the top left corner,

as showed into the following image:

 

To insert a prefab into a loaded scene click on the prefab icon you want to insert and Drag it from project browser into the scene viewport,

as showed into the following image: