So it's very simple:
You have circles and crosses. The goal is to place the round in a table (variable size) according to the orders which are in-line head and the table columns. These orders are in the form of numbers (1, 2, 3 or 4) that indicate the number and order of the round to be placed in the row or column. For example, if you have a 2 in a column header, that means you have to place 2 circles side by side in this column. If you have a 3 and 2, then you have to place 3 balls side by side and 2 other side balls next in this column. It's the same for the lines. Finally a table requires that all order (columns and rows) are fulfilled.
Another thing: when you finish a painting, you save money. When you have more than 60 pieces, you can "buy" the current table if you find it too hard, clear, so you will spend the next level for 60 balls. We buy a picture by pressing the F1 key.