There is now an online course to go with my book on model averaging. This provides an up-to-date overview of the topic, from both the Bayesian and frequentist perspective, including methods that are popular in machine learning, such as bagging and stacking. Recent developments, published since the book came out in 2018, are also covered, including confidence distributions, the frequentist analogue of posterior distributions.
There is emphasis on understanding the theory underlying the methods and on experience using the methods in RStudio.
Cost: US$200 (+ applicable taxes) for 30 days access. You can find more information and registration details here