Firstly,
In the "metadata setup", part 3: "Metadata folder schemas", the URL link looks wrong.
The link is the same as part 2 content. please fix it.
Secondly,
I completed all 5 steps, and each steps progress becomes completed (likes, 3/3 or 5/5 etc..) But, as the result of "Configuring AEM Assets for Administrators" is still stayed at "90%" progress. it looks an error.
Regards,
-Taishi