I recently learned about decarboxylation from Chef Payton Curry at his cooking demo in DC. It’s pretty simple! When you decarb cannabis, it turns the THCA (non-psychoactive but great anti-inflammatory) into THC (the fun stuff!)—all you need to do is heat it up in the oven or your sous vide water bath!
Once the THC in the cannabis is activated you can pour it into your butters, fats, sugars, and alcohol to cook with.
I personally prefer the sous vide method for accuracy, convenience, and discretion—you can just seal up your cannabis in a zip bag using the water displacement method or with a vacuum sealer, submerge underwater at 95ºC (203ºF) for an hour, and there will be no smell!
If you want to use your oven to decarb, The Stoner Cookbook has a really great time and temperature chart to reference!