Think of it like reading a book. Working left to right across the page, top to bottom. The sequence from the last square on the right hand side of row 1 continues on to the first square on the left of row 2, just as words in a book do.
You need to follow the dots around each square, they should move clockwise around the square. Top left, top right, bottom right, bottom left then back to top left etc.
Whenever a dot goes out of sequence, you have to cross through that square, then carry on the sequence as if you started again from the incorrect entry you just crossed through.
So for example, if it goes, top left, top right, then bottom left, you strike through the bottom left as it has gone out of sequence by skipping bottom right. Then you start the pattern again from the incorrect bottom left, so the next correct entry should be top left, if it is carry on, if not strike through that one too, and so on...
Hope that makes sense & helps? I cant think of another way to describe it