Hi Georgi
For this you will likely have most of the processing work inside of your scheduled event.
You can have a daily scheduled event which checks if there are any reminders it needs to send.
For example: retrieve all of the events which are exactly one week away (compare to the current date time). All relevant events can then be forwarded to a loop. Since you have the CurrentUser in association, you can retrieve their account information, and thus their email address. Afterwards, for all events, you can create an email from template, or from scratch and send it via the email connector.
I do think (in this case) that that is all you need. Of course, it may be that it is more complex in reality.
Let me know!