You can add Comment plugin from Add element wizard
Now, set all the settings of Comment plugin
Custom Date Format: Check this checkbox to use custom date format to display in Comment list.
Date Format: You can use any of the standard date format as well.
Time Format: You can use any of the standard time format as well.
Captcha Settings: You can set whether to display Captcha or not. You can select one of the options from below:
If you are using Free version and have enabled captcha then Image Captcha will be displayed at comment form.
If you select Image Captcha, you need to rename _.htaccess file to .htaccess at this folder /typo3conf/ext/ns_comments/Resources/Private/
Add User Image: Add user image to display for all commments.