Space, mistakes and help
Check the keyboard name and the letters on your own keyboard before starting.
Progress stays on this device.
Use a thumb for a space. A wrong letter stays in place: release it and try the expected letter. You do not need Backspace. Tab moves to help; typing pauses when focus leaves practice.
Try f j. Open help with Tab, return to practice, then confirm that you know what to do after a mistake.
f j
f · left index finger
Help
Made a mistake? Press the correct key; there is no need to erase.