MuseScore Tour - Get Help
There is no one right way to get started learning about MuseScore. This tour is certainly a beginning, but it focuses more on what's possible than on how to do it. MuseScore provides "official" documentation via its Handbook, but the vibrant user community and other online resources on musescore.org are the real story here.
One resource many newcomers find useful is the series of video tutorials produced by MuseScore power user Katie Wardrobe courtesy of her site musescoretips.com. You may have seen these on the musescore.org front page. Do yourself a favor - watch them. They will probably answer most of the questions you might have.
If you search on YouTube, you will find more tutorials submitted by other users, and those are worth watching as well.
There are also written tutorials submitted by users and available on musescore.org. Some of these are quite in-depth, covering a topic in great detail.
Your official source of information on how to use MuseScore is the Handbook. The Help menu in MuseScore gives you access to a local PDF copy that is installed along with the application, and it also links to the online version which may have been updated and improved since you installed MuseScore. As you may have noticed, many of the feature descriptions in this tour link to the corresponding Handbook sections so you can learn how to do almost everything covered in this tour.
When you have questions the handbook cannot answer, try the forums. Open source software in general is rightly hailed for its active user community. The MuseScore user community is particularly supportive even by open source standards. If you ask a question in one of the forums, chance are a knowledgeable fellow user will respond within hours and you'll be on your way. And who knows, maybe you'll be able to return the favor some day.
The MuseScore community has been producing a growing series of short tutorials called "how-to's" that are intended to be short and simple, each dealing with a single topic. Some are written, others use video, others both.
MuseScore: The Essential Beginner's Guide
Just because MuseScore is open source doesn't mean its ecosystem cannot and does not include commercial products. Katie Wardrobe - the creator of the excellent video series referenced above - has also produced this fine ebook. It covers most of the basics you would need to know and is beautifully presented, and she sells it for a reasonable price.
The list of books that can help you with MuseScore is growing. Check out the list.
If you should find a bug or have an idea for a feature, the issue tracker is the place to report it officially. However, a bit of friendly advice: until you really know your way around, it is usually best to post in the Support & bug reports or Feature request forums first, to be sure that the bug / feature in question is not already fixed / implemented.