Press Next to start the tutorial
Check the numbers in the margins. They indicate groups of filled squares...
"4" means 4 filled.  "2-1" means 2 filled, at least 1 blank, and another filled, in that order.
Try to begin with complete rows or columns, or ones with only one possible solution.
 
 
Green indicators means a correct number of filled squares, red means too many squares in that row or column...
 
^