CiviCRM in a NEOS website
I take it you have already read that CiviCRM is designed to work with only the following 4 CMS: Drupal, WordPress, Joomla and Backdrop.
Therefore I assume you are asking a question more along the lines of 'how can I embed a form for event registrations on a standalone CMS?'
There are tools (RemoteForm, CMRF) that allow for this but they still all require CiviCRM to be set up with D, WP, J or B but will then capture the data from a from on an external website. Suggest you read
How can I connect my website to CiviCRM on a remote server?
https://civicrm.org/blog/jamie/display-civicrm-forms-on-any-web-site-anywhere