From your site dashboard, select one of the Find out more buttons on either the Nutrient Calculator, N-Max Calculator or Pesticide Stocks:-
This will bring up a new window where you can activate both calculators and the stocks function.
On the pop-up, click Activate Service. Read through the terms and conditions and select Activate Service again at the bottom:-
Click on the remaining icons and repeat the above step if you wish to activate the N-Max and Stocks functions.
Once these are activated, they will appear as below:-