Treasure Trails/Guide/Lockboxes

Lockboxes are available from Treasure Trails.

Solving

 * 1) Solve the top row and all the other rows except the bottom one
 * 2) Look at the bottom row for the one you want to change and click the tile in the first row of the same column
 * 3) Solve the first row by clicking on the second row
 * 4) Do this until only the bottom one is unsolved
 * 5) Keep repeating until it's eventually solved