I created a trigger for a table in SQL Server and it works for me.
My problem is: How do find it and modify it?
I use this query to find my triggers:
select * from sys.triggers
This find all triggers, but how to open it and change the triggers?
You can do this simply with SSMS. Just go to your table name and expand the Triggers node to view a list of triggers associated with that table. Right click to modify your trigger.