i am not bale to make the youtube tutorial

Hi,
i am trying to make this tutorial>

i am doing just like in the video but i am stuck at the minute 20 when there is attached an collider and the character does not more falls down.
but in my case it continue to fall and i don't know why. so can somebody do me a favor and help me?

i have exported the package which u can find in this link:
https://www.dropbox.com/sh/i8v7o64dwyanb0v/AAD_omfO__PXcoxmC31ElM_ka

i have there also a picture. i have not properly understood what is the difference between the "shot 1" and "shot 2"



i thank you in advance for the help

 

Did you attached a box collider to your ground?