Great question!
In truth, we think our very best training course for someone who is new to both DaVinci Resolve and the practice of color grading is our Resolve 12 & 12.5 Training Bundle. Once it teaches you the fundamentals of the Resolve User Interface, then it takes you through the practice and craft of color grading. The Bundle is almost 25 hours of training.
Then, you can follow that up with the What's New In Resolve 14 Course, designed to get you up to speed on Resolve 14.
Then: For a variety of reasons, we don't currently have a What's New in Resolve 15 Course. Instead, you can use our Membership Library to get up to speed on the major new features in Resolve 15.
If you decide to follow our plan for learning, you can download and install each version of Resolve, as you take the Courses, from this page on Blackmagic's website (scroll down under the 'Latest Downloads' column and choose the version of Resolve that does NOT say 'Studio'. As you do so, be sure to follow our install, uninstall instructions, to minimize problems.
Background information about our Course release schedule
Keeping our training updated for all levels of colorists (from raw beginners to experienced professionals) is difficult to do with Davinci Resolve. Generally, Mixing Light doesn't record training using Beta versions of DaVinci Resolve. Why? Too many significant changes occur during its Beta cycle.
Once Resolve comes out of beta, there's usually a several week pause as we wait for the Blackmagic Certified Syllabus to be released (since we produce Certified training courses). Then it takes about 8-12 weeks to fully produce a training title we can offer for sale. This leaves a short window for us to generate sales before the next beta version of Resolve comes out (suppressing sales for our 'just released' Course).
As a result - you can expect a 2-3 version gap between our 'big' Courses, filled by smaller Courses. Or filled by our Insights Membership Color Grading Library (which is a continuing education product).