In this video, I show an analysis of a multiple process recording. This is a good way to get oriented in a profile to understand what's going on. It goes through finding the data you are looking for, and understanding the timeline of events. It covers garbage collection, and memory usage. It looks at how to make code more parallel, and understanding the timeline of performance profiling data.
Firefox Profiler: https://profiler.firefox.com/
Documentation: https://profiler.firefox.com/docs
DevTools open/close profile: https://share.firefox.dev/3fQemiW