Hello there,
I’m pretty much new here and and new to game development as well 
First of all I have to tell that Rick is an amazing teacher. I am really excited about following this course and improving my coding skills.
Just have a simple question, it might be silly 
but in this lecture Rick has kindly provided us with the graphics, PNGs we need to add into our project. So, in the future in our own projects do we need to create our own graphics with a graphics designing tools or are there any available graphics that we can use in Unity here? like default graphics for grass, mountains, clouds etc. ? or places we can find those graphics we need?
Please bear with me, I am a newbie to these stuff … need some directions here