Not sure I understand the question but here goes.
If you have a TestStand Container (Locals.MyContainer) which has two fields, Num1 and Num2 which are Numbers and you also have a TestStand Array of Numbers.
To pass the element0 of the array to Num1 of the container use
Locals.MyContainer.Num1 = Locals.MyArray[0]
Hope this answers your question.
Regards
Ray Farmer