Variable dice simulation total

I've created dice in Excel, but now I'm trying to calculate the value of the dice based on x amount of dice. ie if I want 3d6, it only pulls values of 3 dice instead of all 15. Would I use COUNTIF or how else do I go about this?

Edit: I have no clue how to share an excel file, if someone tells me how I will.

You could try using the SUM function on a selected range for just the dice you want to add. You might also want to organize data in rows or columns to make it easier.