When Dottie launches, it shows the standard macOS open panel. Click New Document to start a new canvas, or choose an existing file to open. You can also choose File > New Command+N at any time.
A new document opens the New Document sheet, where you set the canvas up before drawing:
Preset: choose Custom to enter any width and height, or pick a preset. Sprite presets cover common sizes (8×8, 16×16, 32×32, 64×64), and system presets match classic hardware—Apple IIc, Atari ST, DOS, Electronika BK, Famicom, Game Boy Advance, Game Boy Color, Macintosh, Mega Drive, and Super Famicom. Choosing a preset fills in the fields below; typing a size just relabels the preset as Custom. You can define your own presets in Settings ▸ Presets.
Width and Height: the canvas size in pixels, up to the maximum canvas size chosen in Settings (1024 per side unless raised).
Pixel Aspect: the shape of each pixel. Leave it 1 : 1 for square pixels, or use a system preset’s ratio (for example the Famicom’s wider 8:7 pixels) so the canvas displays the way that hardware did.
Palette: load a matching colour palette, or leave it Default to keep your current palette. System presets suggest a palette automatically.
Background: fill the canvas with the primary colour (Black), the secondary colour (White), or leave it Transparent (the eraser colour).
Tip Set the values you use most as defaults in Settings, and turn off Show setup dialog to skip this sheet entirely. Holding Option while creating a document also skips the sheet and uses those defaults.