• Head over to the Supabase website.
• Log in to your account, and find your way to the dashboard.
• Click on "New Project" to start a new project if you haven't done so already.
• Fill in the necessary details like project name, database password, and region.

• Once your project is ready, go to the "Database" section from the left sidebar in the Supabase dashboard.
• Click on "SQL" in the submenu to open the SQL editor.

• In the SQL editor, you first need to create a function that the trigger will call.

• For example, to log changes to a users table, enter and run the following SQL command:

  ```sql
  CREATE OR REPLACE FUNCTION log_user_changes()
  RETURNS TRIGGER AS $$
  BEGIN
  IF (TG_OP = 'UPDATE') THEN
  INSERT INTO user_log (user_id, changed_at, change_type)
  VALUES (NEW.id, current_timestamp, 'update');
  RETURN NEW;
  ELSIF (TG_OP = 'INSERT') THEN
  INSERT INTO user_log (user_id, changed_at, change_type)
  VALUES (NEW.id, current_timestamp, 'insert');
  RETURN NEW;
  ELSIF (TG_OP = 'DELETE') THEN
  INSERT INTO user_log (user_id, changed_at, change_type)
  VALUES (OLD.id, current_timestamp, 'delete');
  RETURN OLD;
  END IF;
  END;
  $$ LANGUAGE plpgsql;
  ```

• After creating the function, you can go ahead and create the trigger itself.

• Enter and run the following SQL command to create the trigger for the users table:

  ```sql
  CREATE TRIGGER trigger_log_user_changes
  AFTER INSERT OR UPDATE OR DELETE ON users
  FOR EACH ROW EXECUTE FUNCTION log_user_changes();
  ```

• To make sure the trigger is working correctly, perform some test insert, update, and delete operations on the users table.

• Check the changes by querying the user_log table:

  ```sql
  SELECT * FROM user_log;
  ```

• You should see corresponding entries in the user_log table that confirm the trigger is logging changes properly.

• To disable a trigger, use the DISABLE TRIGGER command:

  ```sql
  ALTER TABLE users DISABLE TRIGGER trigger_log_user_changes;
  ```

• To re-enable a trigger, use the ENABLE TRIGGER command:

  ```sql
  ALTER TABLE users ENABLE TRIGGER trigger_log_user_changes;
  ```

• To drop a trigger, use the DROP TRIGGER command:

```sql
DROP TRIGGER trigger_log_user_changes ON users;
```

• Modify the trigger or function as needed and save the changes using the SQL editor.