Where is this button the tutorial speaks of?

Thank you Fen. Here are few more inconsistencies I found earlier. Can you report these as well? Also, if I encounter problems in the future with the tutorials, should I post them here or somewhere else?

These keys should be “Command + Option” on a Mac:
cmd option.png

In the “content browser walkthrough” the tutorial says to locate the sources panel button, but it doesn’t appear next to it. I eventually found it was the little drop down box to the left of “Filters,” but I had to do a search and try different interface buttons to figure that out: