Add hotkeys to tools or menu items to allow quick access.
If you type a single letter, you can only use that hotkey when single key hotkeys are on (see Turn single key hotkeys on or off).
Hotkeys show up next to the names of menu items in the menus.
Paint hotkeys are listed in the Special:Paint section, near the bottom of the editor.
All the functions accessible through the menus of the Canvas Layer Editor are listed in the Special:Canvas Layer Editor section.
See Windows > Editors > Canvas Layer Editor.
However, you can map the rest of the function keys. Do not change any of the modify hotkeys. A modify key is a hotkey that involves a mouse click-drag-up in conjunction with pressing a key (for example, modifying the radius, opacity, or size of a brush).
When single key hotkeys are on, you have to press or click in the prompt line before you can type tool input (such as coordinates).