Trigger To Insert Records In The Same Table?

we have various user defined fields, so when the user insert new value to this field , i want new records (other user field to get populated) be inserted relevant to the inserted value FROM another table (lookup)

This field is a drop down list , after insert committed , i want other user defined field to populate.

Scenario. Drop down is a list of users, after selecting and updating then i want contact details of the above selected user be populated.

CREATE TRIGGER User_Defined_field_KAE
ON [dbo].[AMGR_User_Fields_Tbl]
AFTER
INSERT

AS

INSERT INTO [dbo].[AMGR_User_Fields_Tbl]
(Client_Id,
Type_Id,
name
SELECT
Client_Id,
'1089',
A.USER_PHONE_1
FROM inserted , [dbo].[ADMN_User_Details] as A
WHERE name = a.user_id;