Put up to 3 orbs in each empty cell such that each numbered cell indicates how many orbs it sees (diagonally and orthogonally).
A numbered cell sees every neighbouring cell - a maximum of 8 cells. Each empty cell must have at least 1 orb.
All puzzles are solvable without guesswork, but the hint button's always there to show you a deducable group or cell.
Click 'examples' for more info on solving techniques.
When a numbered cell sees only one orb cell, the orbs must be the same as the number.
When a numbered cell shows 3, for example, and it only sees 3 empty cells, each of those cells must have only 1 orb.
Likewise, say a numbered cell shows 6 and it only sees 2 cells, then each cell must have 3 orbs.
Otherwise, you may have to get creative. Find groups of empty cells that sum to a number, then consider how other groups of empty cells interact with that group.