How can we implement custom NSComboBox using NSComboBoxCell

Question

I am new to OS X. I am trying to implement a drop down using the NSComboBox. I need to customize that, for this, I found NSComboBoxCell component in the storyboard. But did not find the implementation steps for this.

I need to open a drop down list with a label and check box button when the drop down expand.

Can anyone tell me how can we customize the NSComboBoxCell in OS X.

I want to customize the drop down list.

Any help will be appreciated.

Thanks