Auto populating a Query with a Form

Thanks for the opportunity to ask this question. Please I am now learning access DB so pardon me if my question is fundamental.

I have 2 tbls as follows:
DEPT (TBL 1)
d_DeptID (autonumber) - PK
d_Dept Name

EMPLOYEE (TBL 2)
e_EmpID (autonumber) - PK
e_DeptID (number) - FK
e_LName
e_FName

From these tables, I have the query below:
EMPLOYEEDATA
e_EmpID
e_LName
e_FName
e_DeptID

I have created a form and now my problem is that I want to be able to auto populate the e_DeptID field from the DEPT (TBL 1) the using this Data Entry Form. Because allowing a user to enter such a key field can cause a disaster.

Assistance from anyone will be greatly appreciated.

DeptName