Turn off auto-rotate and rotate your device to play in landscape. Tap the top-left corner to pause the game.You can also touch anywhere in the same column if it's easier.Touch the arrow keys on your side as notes reach the judgement line.Old Input has the anti-mashing system built in, while New Input lets you mash away. Your device should have 2+ (ideally 4+) GB of RAM so that levels won't crash on restart. On smaller devices, I'd recommend using downscroll as to not block the notes with your fingers.
(April 21st 2021 - Not adding Week 7 yet, read here.) Mobile browser and touch screen support because beep bo bop