Hi Sergio,
Thanks for contacting us.
We plan to release Custom Code area in the next plugin update. You will be able to insert your custom code via WordPress dashboard into a special text area on your plugin settings page. You custom code added to that area will be stored, so you can keep updating your WordPress, theme and plugin and keep your code saved.
Stay tuned to our latest plugin updates on Twitter (@bestwebsoft).
For now, we recommend to add your custom code in your theme style.css file. Make sure to backup the file if you have autoupdate enabled or plan to update your theme in future. AFter update any custom chages in theme style.css file will be reverted to default.
Feel free to submit a private ticket if you need any additional help or assistance: https://support.bestwebsoft.com/hc
Sincerely,
BestWebSoft Support Team