Listen (and participate!) to the explanation.
When you do think it's difficult, start with:
Assignment 2 on page 84 of the workbook. Then join the explanation on assignment 6 and 7.
Easy peasy? Work on:
Assignment 6 and 7 on page 85 of the workbook. You'll need an atlas!
Continue with Support The Netherlands 3.5.
The continue with Challenge The Netherlands 3.5.