You should have the original post and the new event in two separate tabs, so that you can move between them as you copy and paste elements of your new event.
Open another tab, then create an event using the menu at the top of your page
Fill the date and time fields
Click on the repeat box
This will open a popup screen
Enter the exclusion pattern if required
Completed date, time and exclusion section
Fill in the organiser section
Assign the category
Add a featured image (optional – if you don’t, the calendar will use a generic picture for the category)
Copy and paste text and pictures for the main body of your event
Date, time, location and contact information completed
Once you publish it, your event will appear in the events calendar