x is a hit and - is nothing. A pattern repeats each line, so a line is written once at its shortest: hat: x- is eighth notes for as long as the pattern plays. Lines of different lengths drift against each other until they meet again, which is how a polyrhythm is written: just the lines.
Hear it. Play renders the audio and plays it. Run a cell again while it plays and it starts over from the top.
See it. Bricks: a row per kit piece, a cell per step, counted 1 e & a. Or sheet music: the kit on a percussion staff with the hands up and the feet down, each instrument on a staff of its own, a guitar with its tab, with counts.
Keep it. A notebook is saved on your device as you write, and the sidebar lists them; the notebook’s name opens its menu, to rename, duplicate or delete one. Print makes a PDF of the sheet.
Write more. The reference has three parts. Language is what every cell has: settings, patterns and play. Drums is the kit: its pieces, and steps. Pitched instruments is everything with a pitch: the key, notes and chords.