Question about music notation?

You have to use separate voices for the pinkie and thumb. The pinkie whole-note would be voice 2 since it's on the bottom, the thumb's half-note is voice 1. You'll need a half-rest in voice 1 at the beginning of the measure (this gets placed over the whole-note). All notes and rests will add up to 8 beats since you have two voices for 4 beats.