Add grid from the Table Grid administration page 

• In your Jira administration navigate to Add-ons
• On the left sidebar locate Table Grid admin menu 
• Select Grids tab
• Add Grid using corresponding button on the top right corner of your screen
  

• Associate the field to the appropriate screens. How to define a screen for a custom field

  You need to define screens for the Grid custom field so you can see it on the issue.

  
  

Add a custom field of type Grid Custom Field

You can add multiple grid configurations for one grid using custom field configuration schemes.

• In your JIRA administration navigate to Issues - Custom fields - Add custom field
• Select a Field Type as Grid Custom Field form the list
  
  
• Add the field name and description
• Associate the field to the appropriate screens.

• The field has been successfully created with the default configuration. 

You can see list of grids in the Table Grid administration, under Grids tab.