Ms Sql Trigger Syntax

Question

Please i need help on how to create trigger for this;

Table 1 transactions.Orderdetails
Table 2 Items.Itemdetails

When a record is inserted into the table 1, QuantityInHand in the table 2
should be updated automatically.

Answer 1

create trigger trigger_name
on transactions.Orderdetails
after insert
as
update Items.Itemdetails set QuantityInHand=... where...