Launch Reminders and select a list of reminders you want to add tasks to, or create an entirely new list. Then, click on the little Plus icon in the upper right; this should create a spot for you to make a new reminder. Now, type in your natural language request, like "Meeting with John tomorrow at 11:30".
Reminders will create the actual task, but will also set up a notification to let you know when the event is about. You don't have to create the reminder, select the info button, and put in the details one at a time.