The easiest is to make sure the combo's row source includes all the fields you want to populate (you don't need to show them, just set the column width to 0 for the ones you want to hide but make sure you accurately set the number of columns property).
Then in the after update event of the combo you should prompt if the user want to update\populate then use something like this pseudo-code:
Code:
Me.txtRank=Me.cboName.Column(n) 'would populate txtRank textbox bound to Rank field with the value from column n of the combo's row source -keep in mind that the column collection is 0 based so if n=2 it will actually be the third column
Me.txtGender=Me.cboName.Column(m) '....