Adding combobox to the worksheet

[abhiutd]

hello!
I have req to add a combobox and populate it programmatically when the sheet loads. I find the combobox control in the Forms control toolbar and able to add it in the sheet. But i dont know how i can change the Id of the control and i'm not able to access it in the code. Please can someone shed light on the steps i should take to work on my task.
I am very new to excel programming.

Thank You.