We want to modify an existing PHP script

We want to modify an existing PHP script. this script ([login to view URL]) will be modified. The modifications we want are as follows; 1. Non-members will not be able to access site content 2. In the "register" section, minor adjustments will be made. 3. Notification system. You will receive a notification when the new contents added or new comments are made, etc. 4. The videos on the current script can be uploaded from YouTube or vimeo. We want videos to be uploaded to our server from desktop or mobile phone. 5. In the Upload section there will be minor arrangements. Some existing things will be removed. 6. we should be able to enlarge the photo when we click on it for a detailed review 7. There are minor faults in the responsive structure of the site. it will be edited. 8. We want users to #mention another user to get his ideas. 9. Transfer of our users on our current site to the new site.