Take your time and wait. Know that learning to garden is a matter of trial and error. I like the iNaturalist app to identify plants (and animals and insects and...) so that should help you figure out what's what. A lot of young or early plants are hard to identify, but you'll pretty quickly learn to recognize your frequent invaders. As for the dead twigs, I like to leave them until late spring so I know if I should expect something else to come up, then either leave them if they're little or cut them back if they're an eye sore. Some plants that are supposed to die back may not if the winter is mild enough, and some plants that aren't supposed to die back might if the winter is severe enough. Some plants will also die back in a particularly harsh summer.
All of that go say take your time. Even the worst "mistakes" are easily fixable.