If you already have a fieldmargin account and farm
Go to account.fieldmargin.com on your browser and log in with your normal credentials
Select the farm that you wish to upgrade
Select which plan you want
On the checkout screen, click on the link next to 'Do you have a Promo Code?'
A box will appear, enter your code in that box
Click outside of the box, if the code is valid it will be applied to your order total
Continue with payment as normal
If you are a new user you will need to register and create a farm first
iOS & Android
On the fieldmargin app click the 'Create an Account' button, set up your login details and register
Follow the instructions for creating a farm
Once you have set up your farm go to account.fieldmargin.com and follow the instructions as above logging in with the details of the account you just created
Web (Laptop or Desktop)
Go to notes.fieldmargin.com and enter your details to register for an account
Follow the instructions to create a farm
Once your farm is set up click the 'Upgrade' button at the top of the screen and then follow the instructions above