You'll need an environment template before you can update it. If you need help creating an environment template, check out this detailed article.
Update a Template
Navigate to Environment Templates
Go to the "Environment templates" section from the navigation pane on the left.
Select the Template
Choose the template you want to update.
Modify Settings
Adjust any parameters or configurations as needed.
Save Changes
Click on the "Save Changes" button to apply the updates to your template.
To know how to delete an environment template click this detailed article.