Based on your skills and experience, I recommend one of the following options
Option 1: Become an MPUG member (check out the 1-week trial membership page https://www.mpug.com/membership/trial-8372948/). Watch the on-demand Project 2016 Certification Essentials https://www.mpug.com/microsoft-project-2016-essentials/ training. Though, I doubt if your employer will consider watching on-demand webinars as a certification and give credits. So, better check with your employer before proceeding with this option. If you would like to go with this option and want to learn at your own pace, you can upgrade to premium membership for $119 / year (https://www.mpug.com/membership/) that gives you access to other resources besides certification courses.