Create User_Guide.md

[pitts-mo]

Using README.md as template this is my first attempt at markup and my first attempt at direct contribution to a GitHub project.

UPDATE: Sorry, I have some GitHub learning to do. I see this looks ugly and likely needs format changes. I also realize inclusion of the purchase link around line 3 may be a good idea.

If you like this work and you're buying Eachine PRO58 please use this link: Eachine PRO58 (It's a reflink)