A field is simply a collection of sensor stations and base stations. To add a field, navigate to the fields page and click the green plus sign in the bottom right-hand corner of the page:
From there, you will see the following dialog box:
Here, you can name your field and record the type of irrigation you use. Select the base station and sensor stations that are in your field.
If you have trouble remembering which pieces of hardware are in your field, click the green map icon in the upper right corner of the page.
Once you're finished naming the field, recording your irrigation system, and selecting the hardware located within the field, click 'Create.'
The new field will show up on the field page, along with any other fields you already created: