MySQL Workbench - Trigger and Stored procedures

We got 3 tables: Project, ProjectWork, Employee Project: Project INT PK, Projectname VARCHAR ProjectWork: Project FK, Emp INT FK, Hours INT, SumHours INT Employee: Emp INT, PersonalId INT, Lastname VARCHAR, Firstname VARCHAR. I need somebody with experience with triggers to give me 3 triggers: - If I insert new project into projectwork table ---> increase sumhours by the hour value i add. - If I delete a project with its primary key (pk), the trigger shall reduce it by the same hours removed in the sumhours column. - if i update the projectwork row, like from 4 to 5 hours, sumhour should go up too. The whole meaning is too have different sumhours for the different project foreign keys in the projectwork tabell. All in all easy task, just not so experienced with triggers.