Where can I find the BeginPlay in the character class?

I am currently following a tutorial on importing a weapon into UE4. I have the basics down, however when I play the editor, the weapon is pointing straight up. The uploader then posted a solution saying to find the BeginPlay in the Character Class, and I can’t find it. Any helps on this dilemma?

Unreal Engine C++ Tutorial - Making a gun! - YouTube This is the tutorial I am following