This project is all about learning how to do the following... and maybe that's not how to do it.
To get started on this project, you should start reading up about PHP and mySql or other database structures. My web host supports PHP and mySql, so that is probably what I'll eventually use.
If you would like to join this project, please join my STEAM Clown Slack channel.
Maybe start with a repl.it project that lets you do an hlml page with jscript. You will want to create a input form to collect the following data. Probably want to stor it in a tuple form, so that later you can pass it to a PHP scripts and write it to a data base.
The next step would be to have the PHP and sQl be able to pull the data and dynamically build a web page that has the headings "Today", "Tomorrow", "This Week", "Next Week", "Soon", "Next Month", "Distant Future", and adds each event under the correct heading based on the event-when-date var.