I ran into some problems immediately when trying to follow the linked tutorial (as detailed in another post Very Basic FPS Help Needed: Compile Errors), and it turns out that it’s because I was using GameModeBase instead of GameMode derp. But there doesn’t seem to be an option for GameMode (nonbase???) in the UE4 C++ wizard.
I’m sure it must be a fairly simple process to set up this class manually but I can’t find… anything on the internet that tells me exactly how. I’m wondering if it would do the trick if I just changed the #include line in the header by deleteing “Base” and all of the references haha, but I’m not at home to try now. So 
Anyway, if anyone could help a nerd out here, I’d appreciate it…