Drop Down List & Dependent Values to be populated

Hi,

Please refer attached file. this is for preparation of structural MTO. In "MTO" sheet in need to populate value from "Detailed MTO" sheet.
I am looking for (In MTO Sheet)
1. Drop down list for column A (Source column B of DETAILED MTO sheet)
2. Dependency drop down list for Column B(Source column C of DETAILED MTO sheet)
3. Auto populate value in column C based on column A & B (Source column K of DETAILED MTO sheet). If column D value is greater than 456
4. Auto populate value in column D based on column A & B (Source column K of DETAILED MTO sheet). If column D value is Less than 456

For example i have filled first two columns manually.

please help.