I was facing the same problem and was stuck for many days on that issue. In the new update you don’t have to upload any key, follow the updated steps of uploading to google, the video is mentioned under the same title in the first module of the course. And for the “something went wrong error” i am facing that problem in the weather app though i have followed all the steps properly.
I was facing the same issue and made the project thrice. But the next day I tried to run the project without any changes, it worked. I guess there is some problem with action simulator or maybe due to some network issues. Try uploading again to action simulator by creating new project. May this helps!