I am willing too, but I did a quick check, and it seems an autotrace feature for Affinity Designer is in the works, but it is not implemented yet. With the two tutorials you have up there basically explaining the use of the autotrace features and not really the tools how to work with vector, a tutorial in the same way for Affinity Designer wouldn't make sense, because you would only use it to edit paths, not create them. An Affinity tutorial would either involve a third party app for the initial creation of the vectors, or it would be just a basic introduction into the vector tools and how to use them. Not sure if this is something you are interested in.
In this context, it makes it look more complicated for inexperienced users to use Affinity Designer, even though the UI is much simpler than the other two. Affinity is great if you are willing to hand draw the vectors, or edit existing vector files.
On another topic, for anyone who would like to learn the basics of vector path editing, this is a nice little online game to teach you. The commands will vary dependent on the application you use, but the basics are the same:
http://bezier.method.ac