Explanation

Box 1: LOGON
Logon triggers fire stored procedures in response to a LOGON event. This event is raised when a user session is established with an instance of SQL Server.
Box 2: INSTEAD OF INSERT
An "INSTEAD of trigger" is executed instead of the original operation, and not combining with the operation.
INSTEAD OF triggers override the standard actions of the triggering statement. It can be used to bypass the statement and execute a whole different statement, or just help us check and examine the data before the action is done.
Box 3: DDL
DDL statements (CREATE or ALTER primarily) issued either by a particular schema/user or by any schema/user in the database Note:
You can write triggers that fire whenever one of the following operations occurs:
* DML statements (INSERT, UPDATE, DELETE) on a particular table or view, issued by any user
* DDL statements (CREATE or ALTER primarily) issued either by a particular schema/user or by any schema/user in the database
* Database events, such as logon/logoff, errors, or startup/shutdown, also issued either by a particular schema/user or by any schema/user in the database References:
https://docs.oracle.com/cd/B19306_01/server.102/b14220/triggers.htm
https://social.technet.microsoft.com/wiki/contents/articles/28152.t-sql-instead-of-triggers.aspx
https://docs.microsoft.com/en-us/sql/relational-databases/triggers/logon-triggers?view=sql-server-2017