You don't mention which Mac you have (how old) but assuming your Mac will take Monterey I would think you should just skip Big Sur. If you go to System Preferences > Software Update it will soon tell you whether you can run Monterey at all. How well depends possibly on the age of your Mac. Make sure that you don't have any critical applications that won't run under Monterey. And of course, make sure you have made a good backup of your computer before you start the update. Once you start the update just walk away and let it do its thing. The screen will go black a few times, and there is a temptation to "mess with it" to see where it is at. Don't!
Dave