I think having a mentor is a great idea. As others have said if you belong to a club or shoot in competitions then it might be easy to find one by just asking. For example in my club we have a handgun group that shoots every week in the evening, any member is welcome. Most of the attendees shoot in competitions and almost all of them handlload. In a situation such as this finding a mentor is like falling off of a chair.

I taught myself how to this. True I made some mistakes, typical rookie things but using books and to a lesser extent videos I have at least learned the basics of handgun ammo. The biggest area to make mistakes outside of violating safety rules is buying the wrong gear. I don't know that having a mentor will totally avoid that problem as there is a wide variety of tools that we use and there is a lot of overlap with respect to functionality.

As others have said you need a good manual anyway so the Lyman is a good place to start. Get a used 49th edition off amazon or Lyman publishes paperback editions they also make a handgun manual. A lot of handloaders recommend the ABC book I don't have it but I do have a book titled Handloading for Handunners by Patrick Sweeney. This is a good book to have on the shelf. I guess what I'm saying is don't let the lack of a mentor stop you if you have the desire to do this you will figure it out.