custom group with filter

[rahul_mishra]

in cloud looker i want to create a chart from explore, my kpi is all events created by month and counts of events whose user have another events for e.g. a event has a user, the same user can have a another event, both events are created in 2 seperate months. i need tp count only those events having user in multiple events month wise.
How to create a chart from this explore where the user view is joined to event view. is there any way without creating a seperate derived table or view to achieve this.