1) Box 1 lets you know that Dopey and Doc are in the first row.
2) Box 9 places Dopey in the middle column in Box 4, leaving Doc in Box 7.
3) Box 7 lets us know that either Grumpy or Bashful is in Box 8.
4) Box 4 indicates that Bashful, the only dwarf with 7 letters in his name, must be in the first column with a dwarf with a 6-letter name. This leaves Grumpy in Box 8.
5) Box 8 indicates that Sleepy and Happy must be in the second row, since they, along with Grumpy, all have a ‘P’ and a ‘Y’ in common. Since Sleepy’s name has six letters, he must be in Box 2 to be in the first column with Bashful. This leaves Happy in Box 5 and Sneezy in Box 6.