Do you want the flow to do the step1 or step2 when you click to edit column in sharepoint list?
The function for clicking to edit column in sharepoint list to trigger the flow is not supported in microsoft flow currently.
Microsoft flow flow could onlu support to trigger the flow with trigger below:
1.Manually trigger a flow.
3.For a selected item (or file in sharepoint list).
You could consider creating a flow with trigger "Manually trigger a flow" or Recurrence, and then add actions under the trigger to achieve your requirement for send email reminder from calendar, and you could run the flow at a custom time.