Trigger to create or update a record?

Hi there, I'm hoping someone can point me the right way. I'm evaluating Ninox for tracking jobs for work, and I'm kind of stuck.

I have a table that will be used to track complete jobs (support tickets) but I need to do some math with these. So my tracking table looks like this (to simplify)

Date, User, TicketID

In case it matters, "User" references a person in a users table. Now, what I want is another table that gets all of the tickets done by a fictional staff member named "Frank", on the date of, say Jan 23 (today) and get a total number of tickets done.

So I have a table for the "Overview" That has these fields that I care about

Date, User, Total Tickets, Hours Worked, Avg Time

What I want to do is if Frank adds 14 rows with TicketID's on the 23rd, The "Total Tickets" should say 14 where the User, and date matches. Sue could add 18 tickets, and for that record it would say have that total.

The end goal is to have the total tickets divided by timed work to give an average of time on each ticket.

Any pointers where to start on that. I can't do a count based on specific fields matching, so I think triggers are the way to go, but can't find a way to update a record in a different table based on matching conditions.

Thanks in advance!