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Access custom fields settings
Click Settings > Issues on the top right hand corner.
Click Custom fields under Fields section on the left panel.
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Creating the custom field
Click on the Add custom field button.
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Click All or Advanced, search for RAG Status Field, select and click Next.
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Fill in the necessary information, then click Create.
Select the screens to add field to and click Update.
Configuring the custom field
On the View custom fields page, click Settings > Configure on the field that you wish to configure.
Under RAG options, click Edit RAG options.
Select Display Type and Hide Text? (if you do not want the text Red / Amber / Green for the field) and click on Update.
Click Done to return to the previous page.