Enter digits in the grid; you can use arrow keys on keyboard or click / touch.

Hover over (or touch on mobile) any cell to view the digits it could be. This updates automatically whenever a cell changes.

Use 'Save' to store the current puzzle state so you can return to the beginning if you want.

Use a combination of different search methods to solve the puzzle. You should wait till one search has finished before doing the next. Although it will let you trigger multiple searches at once and it looks cool, it will probably fail to solve..

Use the arrow keys to scroll backwards and forward digit by digit