You are not trying hard enough. 
The amount of online information about Unreal Engine 4 is kinda staggering. I did test searches for “unreal score system” and “unreal enemy spawn” and got pages of hits for tutorials, video tutorials, forum posts, answerhub, etc. For “unreal endless runner”: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums.
Granted, it’s easy to get information overload. So, I’d suggest: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums.
I do get the “can I have a book, please?” angle. I’ve always had the best success by using multi-stage learning: read it, watch it, try it.