Once you have created Tables for your Project, you can then add Fields to these Tables. Fields define the specific pieces of information that you are capturing about Records in your Table.
If, for example, you were creating a CRM in Gridfox you may have a Table for Companies and another Table for Contacts.
Fields are then added to Tables to describe what you would like to store about the items in the Table. For example, in your Table for Companies you may add Fields for Company Name, Sector and Size.
You can think of Tables like worksheets on a spreadsheet and Fields are the columns in the spreadsheet worksheet.
The users of your application can then add and edit Records in the Tables, where Records are similar to rows in the spreadsheet worksheet.
Fields can be added to your Tables at any time.
If you have made changes to the Fields on your Table, you may want to check the Screens for each of the Tables to ensure they are displaying all of the information that you need.
Also check your User Permissions to ensure that each User can see the appropriate Fields for the Tables.